Bearbeiten von „Non-fungible token“

Ein '''non-fungible token''' ('''NFT''') ist eine einzigartige Dateneinheit, die in einer [[Blockchain]] gespeichert werden kann. Gleichzeitig gilt es als Zertifikat eines digitalen (Anlage-)Objekts, das nicht verändert werden kann.<ref name=":32">{{Cite web|last=Dean|first=Sam|date=2021-03-11|title=$69 million for digital art? The NFT craze, explained|url=https://www.latimes.com/business/technology/story/2021-03-11/nft-explainer-crypto-trading-collectible|url-status=live|access-date=2021-04-08|website=Los Angeles Times|language=en-US}}</ref> NFTs, das können Photos sein, Videos, Audio, sowie viele weitere digitale Dateitypen. Der Zugriff auf die Originaldatei ist jedoch nicht beschränkt auf den Käufer eines NFT. Während Kopien von NFTs von allen erworben werden können, liegt der Beweis des Besitzes fest in einer Blockchain geschrieben. Dieser Beweis ist nicht gleichzusetzen mit einem [[Copyright]].

Im Jahr 2020 verdreifachte sich der Markt für NFTs, auf über 250 Millionen US-Dollar.<ref name=":0">{{Cite web|title=The NFT Market Tripled Last Year, and It's Gaining Even More Momentum in 2021|url=https://www.morningbrew.com/emerging-tech/stories/2021/02/22/nft-market-tripled-last-year-gaining-even-momentum-2021|access-date=2021-04-08|website=Morning Brew}}</ref> Während des ersten Quartals 2021, erzielte der Verkauf von NFTs über 2 Milliarden US-Dollar<ref>{{cite news |last1=Frank |first1=Robert |title=NFT sales top $2 billion in first quarter, with twice as many buyers as sellers |url=https://www.cnbc.com/2021/04/13/nft-sales-top-2-billion-in-first-quarter-with-interest-from-newcomers.html |access-date=1 July 2021 |work=CNBC |date=13 April 2021}}</ref>

== Beschreibung ==
Ein non-fungible token (NFT) ist eine Dateneinheit, welche in einer Blockchain gespeichert ist und verkauft und mit dem gehandelt werden kann.Das NFT kann mit einem speziellen digitalen oder physischen Objekt verbunden sein (Datei, Skulptur, etc.) und die Lizenz zur Nutzung von diesem zu einem speziellen Zweck.<ref name="$69 million for digital art?">{{Cite news|last=Dean|first=Sam|date=March 11, 2021|title=$69 million for digital art? The NFT craze, explained|work=Los Angeles Times|url=https://www.latimes.com/business/technology/story/2021-03-11/nft-explainer-crypto-trading-collectible|access-date=March 12, 2021}}</ref> NFTs (und die damit aosszierten Lizensen zur Nutzung, zum Kopieren oder zum Anzeigen des darunterliegenden Asset) kann auf digitalen Märkten gehandelt und verkauft werden.<ref>{{Cite web|last=Kastrenakes|first=Jacob|date=2021-03-11|title=Beeple sold an NFT for $69 million|url=https://www.theverge.com/2021/3/11/22325054/beeple-christies-nft-sale-cost-everydays-69-million|url-status=live|archive-url=https://web.archive.org/web/20210321215043/https://www.theverge.com/2021/3/11/22325054/beeple-christies-nft-sale-cost-everydays-69-million|archive-date=2021-03-21|access-date=2021-03-21|publisher=[[The Verge]]|language=en}}</ref>

NFTs funktionieren wie kryptografische Token, doch ungleich Kryptowährungen wie z.B. Bitcoin, sind sie untereinander nicht tauschbar; in anderen Worten not [[fungible]] (z.B. entspricht ein Bitcoin dem Äquivalent jedes anderen Bitcoin, während jedes NFT einem anderen zugrundeliegenden Asset entsprechen kann und dadurch sich auch die Werte unterscheiden können).<ref>{{Cite news|title=WTF Is an NFT, Anyway? And Should I Care?|language=en-us|work=Wired|url=https://www.wired.com/story/gadget-lab-podcast-495/|access-date=2021-03-13|issn=1059-1028}}</ref> NFTs werden durch kryptografisches Hashing in einer Blockchain erstellt: einer bestimmten Anzahl Zeichen, die verschlüsselt und randomisiert eine Kette identifizierbarer Blöcke in einer Blockchain bilden.<ref name=":23">{{Cite web|last=Boscovic|first=Dragan|title=How nonfungible tokens work and where they get their value – a cryptocurrency expert explains NFTs|url=http://theconversation.com/how-nonfungible-tokens-work-and-where-they-get-their-value-a-cryptocurrency-expert-explains-nfts-157489|access-date=2021-04-08|website=The Conversation|language=en}}</ref> Diese kryptografische Transaktion gewährleistet die Echtheit jeder digitalen Datei und bietet eine digitale Signatur, mit der ein Besitz des NFTs zurückverfolgt werden kann.<ref name=":23" /> However, data links that point to details like where the art is stored can die.<ref>{{cite news|last1=Kastrenakes|first1=Jacob|date=March 25, 2021|title=Your Million-Dollar NFT Can Break Tomorrow If You're Not Careful|work=The Verge|url=https://www.theverge.com/2021/3/25/22349242/nft-metadata-explained-art-crypto-urls-links-ipfs|access-date=March 31, 2021}}</ref>

==Verwendungszwecke==
[[File:Hashmask 15753.jpg|thumb|Diese Grafik, ''Hashmask'' 15753 (1 von 16.384) von "Suum Cuique Labs GmbH", wurde als NFT über die[[Ethereum]]-Blockchain verkauft.]]
Die einzigartige Identität und der Besitzt eines NFT werden über die jeweilige Blockchain verifiziert.<ref>{{Cite news |date=March 13, 2021 |title=Want to Buy an NFT? Here's What to Know |work=The Wall Street Journal |url=https://www.wsj.com/articles/want-to-buy-an-nft-heres-what-to-know-11615647601 |access-date=March 14, 2021}}</ref> Der Besitz eines NFT wird oft verbunden mit der Lizenz das digitale Objekt zu nutzen, doch generell geht das Copyright nicht in den Besitz von KäuferInnen über: manche Lizensen werden nur zur persönlichen, nicht-kommerziellen Nutzung gewährt, während andere dies explizit erlauben.<ref name="mondaq">https://www.mondaq.com/canada/copyright/1067734/nfts39-nifty-copyright-issues-</ref> 

=== Digitale Kunst ===
[[Digitale Kunst]] war sehr früh ein Anwendungszweck von NFTs, da die Einzigartigkeit des Kunstwerks mühelos durch die Blockchain-Technologie bestätigt werden konnte. Dies traf auch auf die digitalen Signaturen und den Besitz solcher NFTs zu.<ref>{{cite news|last1=Patterson|first1=Dan|date=March 4, 2021|title=Blockchain company buys and burns Banksy artwork to turn it into a digital original|work=CBS News|url=https://www.cbsnews.com/news/banksy-nft-injective-destroy-art-digital-token/|access-date=March 17, 2021}}</ref> Das Digitalkunstwerk mit dem Titel "Everydays – The First 5000 Days", des Künstlers Mike Winkelmann, auch bekannt als [[Beeple]], wurde 2021 für über 69 Millionen US-Dollar verkauft.<ref>{{Cite web|last=Kastrenakes|first=Jacob|date=2021-03-11|title=Beeple sold an NFT for $69 million|url=https://www.theverge.com/2021/3/11/22325054/beeple-christies-nft-sale-cost-everydays-69-million|url-status=live|archive-url=https://web.archive.org/web/20210321215043/https://www.theverge.com/2021/3/11/22325054/beeple-christies-nft-sale-cost-everydays-69-million|archive-date=2021-03-21|access-date=2021-03-21|publisher=[[The Verge]]|language=en}}</ref><ref>{{Cite news|last=Thaddeus-Johns|first=Josie|date=2021-03-11|title=What Are NFTs, Anyway? One Just Sold for $69 Million.|language=en-US|work=The New York Times|url=https://www.nytimes.com/2021/03/11/arts/design/what-is-an-nft.html|access-date=2021-04-14|issn=0362-4331}}</ref> Der Kauf markierte einen Meilenstein bei Auktionen, war es tatsächlich der dritthöchste jemals bezahlte Betrag, der jemals für einen noch lebenden Künstler bezahlt wurde (nach Jeff Koons und David Hockney). Ein anderes Kunstwerk von "Beeple" mit dem Titel "Crossroad" (Kreuzung), bestehend aus einem 10-Sekunden-Video von animierten Fußgängern, wurde für 6,6 Millionen US-Dollar auf einem Online-Kryptomarktplatz verkauft.<ref name="Reyburn">{{Cite news|last=Reyburn|first=Scott|date=2021-03-11|title=JPG File Sells for $69 Million, as 'NFT Mania' Gathers Pace|language=en-US|work=The New York Times|url=https://www.nytimes.com/2021/03/11/arts/design/nft-auction-christies-beeple.html|access-date=2021-04-14|issn=0362-4331}}</ref><ref>{{Cite web|last1=Solomon|first1=Tessa|date=2021-02-25|title=Beeple NFT Artwork Sells for $6.6 M. Ahead of Viral Christie's Auction|url=https://www.artnews.com/art-news/news/beeple-nft-artwork-nifty-gateway-sale-1234584701/|access-date=2021-04-14|website=ARTnews.com|language=en-US}}</ref>

Ein 3D-Modell eines Hauses mit dem Titel "Mars House" der Künstlerin [[Krista Kim]] wurde als digitales Immobilien-Asset für über 500.000 US-Dollar verkauft.<ref>{{Cite web|date=2021-03-22|title=Artist Krista Kim sells "first NFT digital house" for over $500,000|url=https://www.dezeen.com/2021/03/22/mars-house-krista-kim-nft-news/|access-date=2021-04-15|website=Dezeen|language=en}}</ref>

=== Sammelobjekte ===
NFTs können auch digitale Sammlungen, in dem Falle Kopien, realer Sammelkarten repräsentieren. Im Februar 2021 verkaufte sich eine [[LeBron James]]-Slamdunk-NFT-Sammelkarte auf dem [[National Basketball Association|NBA]]-Top-Shot-Marktplatz für 208.000 US-Dollar.<ref name="Reuters 2021-03-01">{{cite news |url=https://www.reuters.com/article/us-retail-trading-nfts-insight-idUSKCN2AT1HG |title=How a 10-second video clip sold for $6.6 million |work=[[Reuters]] |date=2021-03-01 |accessdate=2021-03-22 }}</ref>

=== Videospiele ===
NFTs können auch [[Game asset|in-game assets]] sein, etwa digitale Ländereien, die von den NutzerInnen statt den VideospielentwicklerInnen kontrolliert werden. NFTs können auch auf Drittmarktplätzen gehandelt werden, sogar ohne explizite Erlaubnis der Spieleentwickler. Im Februar 2021 vermeldete ''Axie Infinity'' den Rekordverkauf in Höhe von 1,5 Millionen US-Dollar für ein Stück digitales Land.<ref>{{cite web |last1=Quiroz-Gutierrez |first1=Marco |title=NFTs Are Spurring a Digital Land Grab—in Videogame Worlds |url=https://www.wsj.com/articles/nfts-are-spurring-a-digital-land-grabin-videogame-worlds-11616414401 |website=Wall Street Journal |date=22 March 2021}}</ref>

=== Musik ===
Die Blockchain-Technologie und das ihr zugrundeliegende Netzwerk gaben MusikerInnen die Möglichkeit ihre Werke in Tokens umzuwandeln und dadurch diese als NFTs zu veröffentlichen. Dies erweiterte die Liste der Optionen für MusikerInnen und KünstlerInnen ihre Werke und Musik zu monetarisieren. Auch die öffentliche Wahrnehmung ließ sich in vielen Fällen dadurch beeinflussen oder gar verbessern. Im Zuge der Verluste durch die [[COVID-19]]-Viruspandemie waren NFTs eine sehr lukrative und clevere Alternative der Einnahmequelle, da ausgefallene Konzerte und Veröffentlichungen die Einnahmen der Musikindustrie bis zu 85% gegenüber Vorjahreszeiträumen fallen ließen.<ref>{{Cite news|date=2020-11-18|title=Musicians will lose two-thirds of their income in 2020|language=en-GB|work=BBC News|url=https://www.bbc.com/news/entertainment-arts-54966060|access-date=2021-05-07}}</ref> 

NFTs were utilized by artists to increase revenue during the COVID-19 pandemic. In February 2021, NFTs reportedly generated around $25 million within the music industry (in an industry with annual revenue of over $20 billion).<ref>{{Cite web|date=2021-03-12|title=Music-related NFT sales have topped $25m in the past month|url=https://www.musicbusinessworldwide.com/music-related-nft-sales-have-topped-25m-in-the-past-month/|access-date=2021-05-07|website=Music Business Worldwide|language=en-US}}</ref> On February 28, 2021, electronic dance musician [[3LAU]] sold a collection of 33 NFTs for a total of $11.7 million to commemorate the three-year anniversary of his ''Ultraviolet'' album.<ref name=":4">{{Cite web|last=Brown|first=Abram|title=Largest NFT Sale Ever Came From A Business School Dropout Turned Star DJ|url=https://www.forbes.com/sites/abrambrown/2021/03/03/3lau-nft-nonfungible-tokens-justin-blau/|access-date=2021-05-20|website=Forbes|language=en}}</ref> 
On March 3, 2021, rock band [[Kings of Leon]] became the first to announce the release of a new album, ''[[When You See Yourself]]'', in the form of an NFT which generated a reported $2 million in sales.<ref>{{Cite news|last=Steele|first=Anne|date=2021-03-23|title=Musicians Turn to NFTs to Make Up for Lost Revenue|language=en-US|work=Wall Street Journal|url=https://www.wsj.com/articles/nfts-are-music-industrys-latest-big-hit-11616491801|access-date=2021-05-07|issn=0099-9660}}</ref> Other musicians that have used NFTs include American rapper [[Lil Pump]],<ref name="Cheddar 2021-03-232">{{cite news|date=2021-03-23|title=CEO of Sweet Talks NFT Partnership with Rapper Lil Pump|work=Cheddar|url=https://cheddar.com/media/ceo-of-sweet-talks-nft-partnership-with-rapper-lil-pump|accessdate=2021-03-29}}</ref><ref name="Vulture 2021-03-182">{{cite news|date=2021-03-18|title=Musician NFT Projects, Ranked by How Many F's I Can Give|work=Vulture|url=https://www.vulture.com/2021/03/music-nft-projects-ranked.html|accessdate=2021-03-29}}</ref><ref name="XXL Mag 2021-03-23-2">{{cite news|date=2021-03-23|title=Rappers and NFTs – How Hip-Hop Is Cashing In on Non-Fungible Tokens|work=XXL Mag|url=https://www.xxlmag.com/rappers-nfts-hip-hop-non-fungible-tokens/|accessdate=2021-03-29}}</ref> artist [[Shepard Fairey]]<ref>{{Cite web|last=Chmielewski|first=Dawn C.|date=2018-08-03|title=‘Deadpool 2’ Jumps On The Digital Collectibles Bandwagon|url=https://deadline.com/2018/08/deadpool-2-jumps-digital-collectibles-blockchain-1202439356/|access-date=2021-05-19|website=Deadline|language=en-US}}</ref><ref>{{Cite web|last1=Halperin|first1=Shirley|date=2021-04-21|title=Mike Dean and Shepard Fairey Team for NFT Offering 'OBEY 4:22' (EXCLUSIVE)|url=https://variety.com/2021/music/news/mike-dean-shepard-fairey-nft-obey-422-1234955424/|access-date=2021-05-07|website=Variety|language=en-US}}</ref> and rapper [[Eminem]].<ref>{{Cite web|title=Eminem's First NFT Drop, 'Shady Con,' Includes One-of-a-Kind Slim Shady-Produced Beats|url=https://www.billboard.com/articles/columns/hip-hop/9561774/eminem-first-nft-drop-shady-con-details/|access-date=2021-05-19|website=Billboard|language=en}}</ref>

=== Film ===
In May 2018, [[20th Century Studios|20th Century Fox]] partnered with Atom Tickets and released limited-edition ''[[Deadpool 2]]'' digital posters to promote the film. They were available from Opensea.io and the GFT exchange.<ref>{{Cite web|title=Deadpool posters can now be bought as NFTs|url=https://www.yahoo.com/entertainment/deadpool-posters-now-bought-nfts-110019928.html|access-date=2021-05-19|website=www.yahoo.com|language=en-US}}</ref><ref>{{Cite web|last=Chmielewski|first=Dawn C.|date=2018-08-03|title=‘Deadpool 2’ Jumps On The Digital Collectibles Bandwagon|url=https://deadline.com/2018/08/deadpool-2-jumps-digital-collectibles-blockchain-1202439356/|url-status=live|access-date=2021-05-19|website=Deadline|language=en-US}}</ref>
In March 2021,<ref name="rarible.com">{{Cite web|title=Claude Lanzmann: Spectres of the Shoah (Exclusive NFT 1st Ed.)|url=https://rarible.com/token/0xd07dc4262bcdbf85190c01c996b4c06a461d2430:287368:0x5bd18a302c34e0c1f5e4a9aac5fffb6b1e4d8e4b|access-date=2021-04-14|website=rarible.com|language=en}}</ref> [[Adam Benzine]]'s [[Academy Awards|Oscar]]-nominated documentary ''[[Claude Lanzmann: Spectres of the Shoah]]'' became the first motion picture, documentary and Academy Award-nominated film to be minted and auctioned as an NFT,<ref>{{Cite web|last=Ravindran|first=Manori|date=2021-03-15|title=NFT Craze Enters Film World: 'Claude Lanzmann' Documentary is First Oscar Nominee to Be Released as Digital Token (EXCLUSIVE)|url=https://variety.com/2021/film/global/nft-movies-first-film-sale-claude-lanzmann-documentary-1234930343/|access-date=2021-04-14|website=Variety|language=en-US}}</ref><ref>{{Cite web|date=2021-03-22|title=NFTs are Confusing Everyone, But the Newest Internet Token is Raking in the Memes|url=https://www.news18.com/news/buzz/nfts-are-confusing-everyone-but-the-newest-internet-token-is-raking-in-the-memes-3559814.html|access-date=2021-04-14|website=www.news18.com|language=en}}</ref> via the Rarible platform.<ref name="rarible.com"/>

Other projects in the film industry using NFTs include the announcement that an exclusive NFT artwork collection will be released for ''[[Godzilla vs. Kong]]''<ref>{{Cite web|last=Bosselman|first=Haley|date=2021-03-31|title='Godzilla vs. Kong' to Have First Major Motion Picture NFT Art Release|url=https://variety.com/2021/film/news/godzilla-vs-kong-first-major-motion-picture-nft-art-release-1234941253/|access-date=2021-04-14|website=Variety|language=en-US}}</ref> and director [[Kevin Smith]] announcing in April 2021 that his forthcoming horror movie ''[[Killroy Was Here]]'' would be released as an NFT.<ref>{{Cite web|last=D'Alessandro|first=Anthony|date=2021-04-13|title=Kevin Smith To Sell Horror Movie 'Killroy Was Here' As NFT, Launches Jay And Silent Bob's Crypto Studio|url=https://deadline.com/2021/04/kevin-smith-killroy-was-here-nft-sale-jay-and-silent-bob-crypto-studio-1234733439/|access-date=2021-04-14|website=Deadline|language=en-US}}</ref> 

=== Sports ===
NFTs have also been used in sports, in September 2019, NBA player [[Spencer Dinwiddie]] tokenized his contract so that others can invest into it.<ref>{{cite news |last1=Arnovitz |first1=Kevin |title=How investing $150K in Spencer Dinwiddie would actually work |url=https://www.espn.com/nba/story/_/id/27853850/how-investing-150k-spencer-dinwiddie-actually-work |access-date=April 1, 2021 |work=ESPN |date=October 21, 2019}}</ref><ref name="The Athletic 2019-09-12">{{cite news |url=https://theathletic.com/1199912/2019/09/12/sources-spencer-dinwiddie-to-convert-his-nba-contract-into-a-secured-digital-investment-heres-what-that-means/ |title=Sources: Spencer Dinwiddie to convert his NBA contract into a secured digital investment. Here's what that means |work=The Athletic |date=2019-09-12 |accessdate=2021-04-01 }}</ref> In addition, Dapper Labs, a blockchain technology-based company, has collaborated with the NBA to create "N.B.A Top Shot", a marketplace for digital highlight clips.<ref name="Reyburn"/>

=== Fashion ===
In 2019, [[Nike, Inc|Nike]] acquired a patent that allows for blockchain technology to attach cryptographically secured digital assets in the form of NFTs to physical products, such as a pair of [[sneakers]], under the name "CryptoKicks".<ref>{{Cite web|last=Beedham|first=Matthew|date=2019-12-10|title=Nike now holds patent for blockchain-based sneakers called 'CryptoKicks'|url=https://thenextweb.com/news/nike-blockchain-sneakers-cryptokick-patent|access-date=2021-04-14|website=TNW {{!}} Hardfork|language=en}}</ref><ref>{{Cite web|last=Clark|first=Mitchell|date=2021-03-03|title=People are spending millions on NFTs. What? Why?|url=https://www.theverge.com/22310188/nft-explainer-what-is-blockchain-crypto-art-faq|access-date=2021-04-14|website=The Verge|language=en}}</ref>

=== Pornography ===
Some porn stars have also tokenized their [[pornography|pornographic]] work, allowing for the sale of unique content for their customers, though hostility from NFT marketplaces towards pornographic material has presented significant drawbacks for creators.<ref>{{cite web |last1=Dickson |first1=EJ |title=Porn Creators Are Getting In on the NFT Craze |url=https://www.rollingstone.com/culture/culture-features/crypto-nft-sex-workers-porn-performers-1142030/ |website=Rolling Stone |access-date=30 March 2021 |date=16 March 2021}}</ref><ref>{{cite web |last1=Cole |first1=Samantha |title='Building the Cockchain:' How NSFW Artists Are Shaping the Future of NFTs |url=https://www.vice.com/en/article/88aybx/building-the-cockchain-how-nsfw-artists-are-shaping-the-future-of-nfts |website=Vice |access-date=30 March 2021 |date=19 March 2021}}</ref>

=== Academia ===
In May 2021, [[University of California, Berkeley|UC Berkeley]] announced that it would be auctioning NFTs for the patent disclosures for two Nobel Prize-winning inventions: [[CRISPR gene editing|CRISPR-Cas9]] gene editing and [[cancer immunotherapy]].<ref name=":1">{{Cite web|title=UC Berkeley Will Auction NFTs for 2 Nobel Prize Patents {{!}} Inside Higher Ed|url=https://www.insidehighered.com/quicktakes/2021/05/28/uc-berkeley-will-auction-nfts-2-nobel-prize-patents|access-date=2021-05-29|website=www.insidehighered.com|language=en}}</ref> The university will continue to own the patents for these inventions, as the NFTs relate only to the university patent disclosure form, an internal form used by the university for researchers to disclose inventions.<ref name=":1" /> The NFTs were sold on June 8, 2021 for 22 [[ETH]] (ca. USD 55,000. <ref>https://foundation.app/@UCBerkeley/the-fourth-pillar-uc-berkeley-2021-41258</ref>

== Copyright ==
Ownership of an NFT does not inherently grant copyright to whatever digital asset the token represents.<ref>{{Cite news|last=Gallagher|first=Jacob|date=2021-03-15|title=NFTs Are the Biggest Internet Craze. Do They Work for Sneakers?|language=en-US|work=Wall Street Journal|url=https://www.wsj.com/articles/nfts-and-fashion-collectors-pay-big-money-for-virtual-sneakers-11615829266|access-date=2021-06-26|issn=0099-9660}}</ref><ref name=":5">{{Cite news|last=Thaddeus-Johns|first=Josie|date=2021-03-11|title=What Are NFTs, Anyway? One Just Sold for $69 Million.|language=en-US|work=The New York Times|url=https://www.nytimes.com/2021/03/11/arts/design/what-is-an-nft.html|access-date=2021-06-26|issn=0362-4331}}</ref> While someone may sell an NFT representing their work, the buyer will not necessarily receive copyright privileges when ownership of the NFT is changed and so the original owner is allowed to create more NFTs of the same work.<ref>{{Cite news|last=Salmon|first=Felix|date=March 12, 2021|title=How to exhibit your very own $69 million Beeple|work=Axios|url=https://www.axios.com/beeple-crypto-nft-art-a4c631d1-d173-46a5-b514-9732b2fcecaf.html|access-date=March 13, 2021}}</ref><ref name=":53">{{Cite news|last=Clark|first=Mitchell|date=March 11, 2021|title=NFTs, explained|work=The Verge|url=https://www.theverge.com/22310188/nft-explainer-what-is-blockchain-crypto-art-faq|access-date=March 11, 2021}}</ref> In that sense, an NFT is merely a proof of ownership that is separate from a copyright.<ref name=":5" /><ref>{{Cite news|date=March 3, 2021|title=NFT blockchain drives surge in digital art auctions|work=BBC|url=https://www.bbc.com/news/technology-56252738|access-date=March 12, 2021}}</ref> According to legal scholar [[Rebecca Tushnet]], "In one sense, the purchaser acquires whatever the art world thinks they have acquired. They definitely do not own the copyright to the underlying work unless it is explicitly transferred."<ref>{{cite web|title=Memes for Sale? Making sense of NFTs|url=https://today.law.harvard.edu/memes-for-sale-making-sense-of-nfts/|access-date=26 June 2021|website=Harvard Law Today}}</ref> In practice, NFT purchasers do not generally acquire the copyright of the underlying artwork.<ref>{{Cite news|last=Burton|first=Amber|date=2021-03-13|title=Want to Buy an NFT? Here’s What to Know|language=en-US|work=Wall Street Journal|url=https://www.wsj.com/articles/want-to-buy-an-nft-heres-what-to-know-11615647601|access-date=2021-06-26|issn=0099-9660}}</ref>

== Standards in blockchains ==
Specific token standards have been created to support various blockchain use-cases. These include the Ethereum ERC-721 standard of ''[[CryptoKitties]],'' and the more recent ERC-1155 standard.<ref name="The bitcoin elite are spending millions">{{Cite web |last=Volpicelli |first=Gian |date=24 February 2021 |title=The bitcoin elite are spending millions on collectable memes |url=https://www.wired.co.uk/article/crypto-art-nft |website=Wired UK}}</ref> The FLOW and [[Bitcoin Cash]] blockchains support NFTs.<ref name="Engadget 2021-03-11 Ref1">{{cite news |url=https://www.engadget.com/nft-explainer-digital-art-collectibles-blockchain-environment-business-investment-cryptocurrency-153023551.html |title=NFTs are both priceless and worthless |work=Engadget |date=2021-03-11 |accessdate=2021-04-09 }}</ref><ref name="Crowdfund Insider 2021-03-07">{{cite news |url=https://www.crowdfundinsider.com/2021/03/172920-uniswap-uni-token-was-shining-star-of-defi-this-past-week-while-ethereum-based-nfts-rising-in-popularity-okex-reports/ |title=Uniswap UNI Token was "Shining Star" of DeFi this Past Week, while Ethereum based NFTs Rising in Popularity, OKEx Reports |work=Crowdfund Insider |date=2021-03-07 |accessdate=2021-04-09 }}</ref>

=== Ethereum ===
ERC-721<ref name="The bitcoin elite are spending millions"/> was the first standard for representing non-fungible digital assets on the Ethereum blockchain. ERC-721 is an inheritable [[Solidity]] [[smart contract]] standard, meaning that developers can create new ERC-721-compliant contracts by importing it from the OpenZeppelin library. ERC-721 provides core methods that allow tracking the owner of a unique identifier, as well as a permissioned way for the owner to transfer the asset to others.<ref name=":2">{{Cite web|title=EIP-721: ERC-721 Non-Fungible Token Standard|url=https://eips.ethereum.org/EIPS/eip-721|access-date=2021-04-05|website=Ethereum Improvement Proposals|language=en}}</ref>

The ERC-1155 standard<ref name="The bitcoin elite are spending millions"/> offers "semi-fungibility", as well as providing a [[superset]] of ERC-721 functionality (meaning that an ERC-721 asset could be built using ERC-1155). Unlike ERC-721 where a unique ID represents a single asset, the unique ID of an ERC-1155 token represent a class of assets, and there is an additional quantity field to represent the amount of the class that a particular wallet has.<ref name=":3">{{Cite web|title=EIP-1155: ERC-1155 Multi Token Standard|url=https://eips.ethereum.org/EIPS/eip-1155|access-date=2021-04-05|website=Ethereum Improvement Proposals|language=en}}</ref> The assets under the same class are interchangeable, and the user can transfer any amount of assets to others.<ref name=":3" />

===FLOW===
The FLOW blockchain which uses [[proof of stake]] consensus model supports NFTs, for example NBA Top Shot is run on the FLOW blockchain. [[Cryptokitties]] plans to switch from Ethereum to FLOW in the future.<ref name="Engadget 2021-03-11 Ref1" />

===Tezos===
[[Tezos]] is a blockchain network that operates on [[proof of stake]] and supports the sale of NFT art.<ref>{{cite news |last1=Sparkes |first1=Matthew |title=NFT developers say cryptocurrencies must tackle their carbon emissions|url=https://www.newscientist.com/article/2272687-nft-developers-say-cryptocurrencies-must-tackle-their-carbon-emissions/ |access-date=March 31, 2021 |work=NewScientist |date=March 30, 2021}}</ref>

== History ==

=== Early history (2012–2017) ===
[[File:Etheria presentation Devcon1.jpg|thumb|Presentation of Etheria at DEVCON 1. November 13, 2015.]]
The first one-off NFT was created on May 3, 2014, by Kevin McCoy and Anil Dash, live at the Seven on Seven conference at the New Museum in New York City. This experiment represents the first time a non-fungible, tradable blockchain marker was explicitly, via on-chain metadata (enabled by Namecoin), linked to a unique work of art,<ref name="dash">{{Cite web|last=Dash|first=Anil|date=2021-04-02|title=NFTs Weren't Supposed to End Like This|url=https://www.theatlantic.com/ideas/archive/2021/04/nfts-werent-supposed-end-like/618488/|access-date=2021-05-05|website=The Atlantic|language=en}}</ref> standing in stark contrast to the multi-unit, fungible, metadata-less "colored coins" of other blockchains and [[Counterparty (platform)|Counterparty]].

In October, 2015, the first fully-fledged NFT project, Etheria, was launched and demonstrated live at DEVCON 1, Ethereum's first developer conference, in London, UK, just three months after the launch of the Ethereum blockchain itself. Most of Etheria's 457 purchasable and tradable hexagonal tiles went unsold for more than 5 years until March 13, 2021, when renewed interest in NFTs sparked a buying frenzy. Within 24 hours, all tiles of the current version and a prior version, each hardcoded to 1 ETH ($0.43 cents at the time of launch), were sold for a total of $1.4 million.<ref>{{Cite web|title=The Cult of CryptoPunks|url=https://social.techcrunch.com/2021/04/08/the-cult-of-cryptopunks/|access-date=2021-05-05|website=TechCrunch|language=en-US}}</ref>

=== Public awareness (2017–2021) ===
In 2017, the Ethereum blockchain started to gain prominence over bitcoin based token platforms, due to Ethereum having a system for token creation and storage built right into its blockchain thus eliminating the need for third-party platforms like Counterparty, and was the company to coin the term non-fungible token. Also in 2017, the American studio Larva Labs released [[CryptoPunks]], a project to trade unique cartoon characters, on the Ethereum blockchain.<ref>{{Cite news|date=2021-03-08|title=Should You Buy a Bitcoin-Inspired Image of Lindsay Lohan?|language=en|work=Bloomberg.com|url=https://www.bloomberg.com/news/articles/2021-03-08/bitcoin-btc-mania-boosts-crypto-art-such-as-a-lebron-video-are-nfts-worth-it|access-date=2021-04-07}}</ref><ref name=":132">{{Cite web|last=Abbruzzese|first=Jason|title=This ethereum-based project could change how we think about digital art|url=https://mashable.com/2017/06/16/cryptopunks-ethereum-art-collectibles/|access-date=2021-04-06|website=Mashable|language=en}}</ref><ref>{{Cite journal|last=Chevet|first=Sylve|date=2018-05-10|title=Blockchain Technology and Non-Fungible Tokens: Reshaping Value Chains in Creative Industries|url=https://papers.ssrn.com/abstract=3212662|language=en|location=Rochester, NY|ssrn=3212662}}</ref> In late 2017, another project called CryptoKitties where players adopt and trade virtual cats was released and quickly went viral, raising a $12.5 million investment and some kitties were selling for over $100,000.<ref>{{Cite news|date=2017-12-04|title=CryptoKitties Mania Overwhelms Ethereum Network's Processing|language=en|work=Bloomberg.com|url=https://www.bloomberg.com/news/articles/2017-12-04/cryptokitties-quickly-becomes-most-widely-used-ethereum-app|access-date=2021-04-07}}</ref><ref>{{Cite web|title=CryptoKitties raises $12M from Andreessen Horowitz and Union Square Ventures|url=https://social.techcrunch.com/2018/03/20/cryptokitties-raises-12m-from-andreessen-horowitz-and-union-square-ventures/|access-date=2021-04-07|website=TechCrunch|language=en-US}}</ref><ref>{{Cite web|last=Cheng|first=Evelyn|date=2017-12-06|title=Meet CryptoKitties, the $100,000 digital beanie babies epitomizing the cryptocurrency mania|url=https://www.cnbc.com/2017/12/06/meet-cryptokitties-the-new-digital-beanie-babies-selling-for-100k.html|access-date=2021-04-07|website=CNBC|language=en}}</ref>

In 2018, Decentraland, a blockchain-based virtual world, raised $26 million in an initial coin offering, and had a $20 million internal economy as of September 2018.<ref>{{Cite web|last=Hankin|first=Aaron|title=People are making more than 500% buying property that doesn't actually exist|url=https://www.marketwatch.com/story/people-are-making-more-than-500-buying-property-that-doesnt-actually-exist-2018-09-04|access-date=2021-04-07|website=MarketWatch|language=en-US}}</ref><ref>{{Cite news|date=2018-06-12|title=How to Make a Killing in Virtual Real Estate|language=en|work=Bloomberg.com|url=https://www.bloomberg.com/news/articles/2018-06-12/making-a-killing-in-virtual-real-estate|access-date=2021-04-07}}</ref>

In 2019, [[Nike, Inc.|Nike]] patented a system called CryptoKicks that would use NFTs to verify the authenticity of physical sneakers and give a virtual version of the shoe to the customer.<ref>{{Cite news|last=Gallagher|first=Jacob|date=2021-03-15|title=NFTs Are the Biggest Internet Craze. Do They Work for Sneakers?|language=en-US|work=Wall Street Journal|url=https://www.wsj.com/articles/nfts-and-fashion-collectors-pay-big-money-for-virtual-sneakers-11615829266|access-date=2021-04-07|issn=0099-9660}}</ref>

In early 2020, the developer of CryptoKitties, Dapper Labs, released the beta version of NBA TopShot, a project to sell tokenized collectibles of NBA highlights.<ref>{{Cite web|title=CryptoKitties developer launches NBA TopShot, a new blockchain-based collectible collab with the NBA|url=https://social.techcrunch.com/2020/05/27/cryptokitties-developer-launches-nba-top-shot-a-new-blockchain-based-collectible-collab-with-the-nba/|access-date=2021-04-09|website=TechCrunch|language=en-US}}</ref> The project was built on top of Flow, a newer and more efficient blockchain compared to Ethereum.<ref name="Engadget 2021-03-11 Ref1" /> Later that year, the project was released to the public and reported over $230 million in gross sales as of February 28, 2021.<ref>{{Cite web|last=Young|first=Jabari|date=2021-02-28|title=People have spent more than $230 million buying and trading digital collectibles of NBA highlights|url=https://www.cnbc.com/2021/02/28/230-million-dollars-spent-on-nba-top-shot.html|access-date=2021-04-09|website=CNBC|language=en}}</ref>

The NFT market experienced rapid growth during 2020, with its value tripling to $250 million.<ref name=":02">{{Cite web|title=The NFT Market Tripled Last Year, and It's Gaining Even More Momentum in 2021|url=https://www.morningbrew.com/emerging-tech/stories/2021/02/22/nft-market-tripled-last-year-gaining-even-momentum-2021|access-date=2021-04-08|website=Morning Brew}}</ref> In the first three months of 2021, more than $200 million were spent on NFTs.<ref name=":12">{{Cite web|title=NFTs Are Shaking Up the Art World—But They Could Change So Much More|url=https://time.com/5947720/nft-art/|access-date=2021-04-06|website=Time}}</ref>

=== NFT buying surge (2021–present) ===
In 2021, interest in NFTs increased. Blockchains such as [[Ethereum]], Flow, and [[Tezos]] established specific standards to ensure that the digital item represented are authentically one-of-a-kind. NFTs are now being used to [[commodify]] digital assets in art, music, sports, and other popular entertainment, with most NFTs part of the Ethereum blockchain, while other blockchains can implement their own versions of NFTs.<ref>{{Cite web|last=Clark|first=Mitchell|date=2021-03-03|title=People are spending millions on NFTs. What? Why?|url=https://www.theverge.com/22310188/nft-explainer-what-is-blockchain-crypto-art-faq|access-date=2021-04-15|website=The Verge|language=en}}</ref> A number of high-profile sales were made just in the first few months of the year.<ref name=":112">{{Cite news|last=Howcroft|first=Elizabeth|date=2021-03-17|title=Explainer: NFTs are hot. So what are they?|language=en|work=Reuters|url=https://www.reuters.com/article/us-crypto-currency-nft-explainer-idUSKBN2B92MA|access-date=2021-04-06}}</ref> In February 2021, the musician [[Grimes (musician)|Grimes]] sold around $6 million worth of tokens representing digital art on [[Nifty Gateway]].<ref>{{Cite web|last=Kastrenakes|first=Jacob|date=2021-03-01|title=Grimes sold $6 million worth of digital art as NFTs|url=https://www.theverge.com/2021/3/1/22308075/grimes-nft-6-million-sales-nifty-gateway-warnymph|access-date=2021-04-07|website=The Verge|language=en}}</ref> Later that month, an NFT representing the meme animation [[Nyan Cat]] was sold in an Internet marketplace for just under $600,000.<ref>{{Cite news|last=Griffith|first=Erin|date=2021-02-22|title=Why an Animated Flying Cat With a Pop-Tart Body Sold for Almost $600,000|language=en-US|work=The New York Times|url=https://www.nytimes.com/2021/02/22/business/nft-nba-top-shot-crypto.html|access-date=2021-04-07|issn=0362-4331}}</ref> On February 28, 2021, electronic dance musician 3LAU sold a collection of 33 NFTs for a total of $11.7 million to commemorate the three-year anniversary of his ''Ultraviolet'' album.<ref name=":4" /> On March 5, 2021, the band Kings of Leon became the first to sell a newly released album, When You See Yourself, in the form of an NFT, generating a reported $2 million in sales.<ref>{{Cite web|last=Hissong|first=Samantha|date=2021-03-03|title=Kings of Leon Will Be the First Band to Release an Album as an NFT|url=https://www.rollingstone.com/pro/news/kings-of-leon-when-you-see-yourself-album-nft-crypto-1135192/|access-date=2021-05-19|website=Rolling Stone|language=en-US}}</ref><ref>{{Cite web|last=Hissong|first=Samantha|date=2021-03-09|title=Music NFTs Have Gone Mainstream. Who's In?|url=https://www.rollingstone.com/pro/features/music-nfts-timeline-kings-of-leon-grimes-3lau-1138437/|access-date=2021-05-20|website=Rolling Stone|language=en-US}}</ref> On March 11, 2021, American digital artist Beeple's work ''[[Everydays: the First 5000 Days|Everydays: The First 5000 Days]]'' became the first NFT artwork to be listed at prominent auction house [[Christie's]] and sold for $69.3 million.<ref>{{Cite web|title=Beeple's masterwork: the first purely digital artwork offered at Christie's {{!}} Christie's|url=https://www.christies.com/features/Monumental-collage-by-Beeple-is-first-purely-digital-artwork-NFT-to-come-to-auction-11510-7.aspx|access-date=2021-04-07|website=www.christies.com|language=en}}</ref><ref name="Beeple Brings Crypto to Christie’s">{{Cite news|last=Thaddeus-Johns|first=Josie|date=February 24, 2021|title=Beeple Brings Crypto to Christie's|work=The New York Times|url=https://www.nytimes.com/2021/02/24/arts/design/christies-beeple-nft.html|access-date=March 12, 2021}}</ref> On March 22, 2021, [[Jack Dorsey]], founder of [[Twitter]] and [[Square, Inc.|Square]], sold an NFT representing his first tweet for over $2.5 million.<ref name=":53" /><ref>{{Cite news|title=The Next Frontier of the NFT Gold Rush: Your Tweets|language=en-us|work=Wired|url=https://www.wired.com/story/nft-art-market-tweets/|access-date=2021-04-07|issn=1059-1028}}</ref>

The speculative market for NFTs has led more investors to trade at greater volumes and rates.<ref name="Beeple Brings Crypto to Christie’s" /> The buying surge of NFTs was called an [[economic bubble]] by experts, who also compared it to the [[Dot-com bubble]].<ref>{{Cite news|last=Reyburn|first=Scott|date=2021-03-30|title=Art's NFT Question: Next Frontier in Trading, or a New Form of Tulip?|language=en-US|work=The New York Times|url=https://www.nytimes.com/2021/03/30/arts/design/nft-bubble.html|access-date=2021-05-03|issn=0362-4331}}</ref><ref>{{Cite news|last=Small|first=Zachary|date=2021-04-28|title=As Auctioneers and Artists Rush Into NFTs, Many Collectors Stay Away|language=en-US|work=The New York Times|url=https://www.nytimes.com/2021/04/28/arts/design/nfts-art-collectors-copyright.html|access-date=2021-05-03|issn=0362-4331}}</ref> By mid-April 2021, demand appeared to have substantially subsided, causing prices to fall significantly; early buyers were reported to have "done supremely well" by ''[[Bloomberg Businessweek]]''.<ref>{{cite news |last1=Tarmy |first1=James |last2=Kharif |first2=Olga |title=These Crypto Bros Want to Be the Guggenheims of NFT Art |url=https://www.bloomberg.com/news/features/2021-04-15/nft-collectors-this-is-who-s-buying-beeple-pak-mad-dog-jones-micah-johnson |access-date=April 29, 2021 |work=Bloomberg Businessweek |date=April 15, 2021}}</ref><ref>{{Cite web|last=Shaw|first=Anny|title=NFT prices are plummeting. What could this mean for the art world?|url=https://www.cnn.com/style/article/nft-bubble-burst-prices-art-world-tan/index.html|access-date=2021-05-03|website=CNN|language=en}}</ref> An NFT of the [[source code]] of the [[World Wide Web]], credited to internet inventor computer scientist Sir [[Tim Berners-Lee]], was auctioned in June 2021 by [[Sotheby’s]] in [[London]],<ref>{{cite news |title=NFT representing Tim Berners-Lee’s source code for the web to go on sale |url=https://www.theguardian.com/artanddesign/2021/jun/15/nft-representing-tim-berners-lee-source-code-world-wide-web-sale-auction |access-date=30 June 2021 |agency=theguardian.com |publisher=theguardian.com |date=15 June 2021}}</ref><ref>{{cite web |title=This Changed Everything: Source Code for WWW x Tim Berners-Lee, an NFT |url=https://www.sothebys.com/en/buy/auction/2021/this-changed-everything-source-code-for-www-x-tim-berners-lee-an-nft/source-code-for-the-www |website=sothebys.com |publisher=sothebys.com |access-date=15 June 2021}}</ref><ref>{{cite news |title=The web’s source code is being auctioned as an NFT by inventor Tim Berners-Lee |url=https://www.cnbc.com/2021/06/15/web-nft-source-code-is-being-auctioned-by-inventor-tim-berners-lee.html |access-date=15 June 2021 |agency=cnbc.com |publisher=cnbc.com |date=15 June 2021}}</ref> and was sold for USD$5.4.<ref>{{cite news |last1=Lawler |first1=Richard |title=Sir Tim Berners-Lee’s web source code NFT sells for $5.4 million |url=https://www.theverge.com/2021/6/30/22557765/www-nft-tim-berners-lee-sothebys-source-code |access-date=30 June 2021 |work=The Verge |publisher=VOX Media |date=30 June 2021}}</ref>

== Popular culture ==

=== Popularity ===
In 2017, NFTs circulated by CryptoKitties, a project developed by Dapper Labs to sell ownership of unique cat avatars, jumped so much in popularity that a surge in demand took up significant transaction space on the [[Ethereum]] blockchain and slowed the entire Ethereum network in December of that year.<ref>{{Cite news|date=2017-12-05|title=CryptoKitties craze slows down transactions on Ethereum|language=en-GB|work=BBC News|url=https://www.bbc.com/news/technology-42237162|access-date=2021-04-06}}</ref><ref>{{Cite web|last=CryptoKitties|title=CryptoKitties {{!}} Collect and breed digital cats!|url=https://www.cryptokitties.co/|access-date=2021-04-06|website=CryptoKitties|language=en}}</ref>

NFTs have become increasingly popular in the early months of 2021 because of recent high-profile sales.<ref name=":112" /> Some notable NFT sales in 2021 like NBA Top Shot's video clip of LeBron James selling for $208,000 on February 22, 3LAU’s album bringing in $11.7 million in sales as of February 28, and digital artist [[Beeple]]'s piece selling for $69.3 million on March 11, have made NFTs an especially current topic in popular culture.<ref name=":112" /><ref>{{Cite web|last=Rapp|first=Timothy|title=LeBron James Lakers Highlight Sells for Record $208K on NBA Top Shot|url=https://bleacherreport.com/articles/2933000-lebron-james-lakers-highlight-sells-for-record-208k-on-nba-top-shot|access-date=2021-04-06|website=Bleacher Report|language=en}}</ref><ref>{{Cite news|last=Reyburn|first=Scott|date=2021-03-11|title=JPG File Sells for $69 Million, as 'NFT Mania' Gathers Pace|language=en-US|work=The New York Times|url=https://www.nytimes.com/2021/03/11/arts/design/nft-auction-christies-beeple.html|access-date=2021-04-06|issn=0362-4331}}</ref> In March 2021 alone, NFT sales exceeded $220 million making up nearly half of all-time NFT sales ever at the time.<ref>{{Cite web|last=Piven|first=Ben|title=NFT craze: Why are non-fungible tokens all the rage?|url=https://www.aljazeera.com/economy/2021/3/26/nft-craze-why-are-non-fungible-tokens-all-the-rage|access-date=2021-04-06|website=www.aljazeera.com|language=en}}</ref> This renewed interest in NFTs, particularly those in art, music, and sports, have made way into mainstream consciousness, especially amongst the [[Gen Z|younger generation]].<ref>{{Cite web|title=What are NFTs and why are they so popular?|url=https://moneyweek.com/investments/alternative-finance/bitcoin/602928/what-are-nfts-and-why-are-they-so-popular|access-date=2021-04-06|website=MoneyWeek|language=en}}</ref><ref>{{Cite web|last=MacColl|first=Margaux|title=These Gen Z VCs are getting in on the NFT frenzy — here are the 4 NFTs they've collected so far|url=https://www.businessinsider.com/here-are-4-nfts-that-owned-by-gen-z-vcs-2021-3|access-date=2021-04-06|website=Business Insider}}</ref> In a March 27, 2021 [[Saturday Night Live]] episode, cast members satirized this growing niche with a comedy skit on NFTs, which was later sold in the form of an NFT for $365,000 on April 6, 2021.<ref>{{Cite web|last=Business|first=Jazmin Goodwin, CNN|title=Still not sure what NFTs are? 'SNL' explains with Eminem parody|url=https://www.cnn.com/2021/03/28/media/nfts-snl-saturday-night-live/index.html|access-date=2021-04-06|website=CNN}}</ref>

Many investors are willing to pay high rates to secure and promote NFTs and continue to do so because they anticipate NFTs to be the biggest and most profitable collectibles in the future.<ref name=":17">{{Cite web|title=If you haven't followed NFTs, here's why you should start|url=https://social.techcrunch.com/2021/02/27/if-you-havent-followed-nfts-heres-why-you-should-start/|access-date=2021-04-06|website=TechCrunch|language=en-US}}</ref><ref>{{Cite web|date=2021-04-02|title=What are NFTs and why are they suddenly so popular?|url=https://www.euronews.com/2021/04/02/what-are-nfts-and-why-are-they-suddenly-so-popular|access-date=2021-04-06|website=euronews|language=en}}</ref> Venture capitalist David Pakman has claimed that the growing value of NFTs is redefining the major entertainment industry as of early 2021.<ref>{{Cite web|title=Why every major entertainment company will get into NFTs, according to the VC behind NBA Top Shot|url=https://news.yahoo.com/why-every-major-entertainment-company-131300843.html|access-date=2021-04-06|website=news.yahoo.com|language=en-US}}</ref> Investors like [[Mark Cuban]] have proposed new ways of implementing NFT technology to monetize sports tickets and merchandise sales.<ref>{{Cite web|last=Locke|first=Taylor|date=2021-03-26|title=Mark Cuban: The Dallas Mavericks are thinking about 'turning our tickets into NFTs'|url=https://www.cnbc.com/2021/03/26/mark-cuban-dallas-mavericks-may-use-nfts-for-ticketing.html|access-date=2021-04-06|website=CNBC|language=en}}</ref>

== Criticism ==
=== Storage off-chain ===
NFTs involving digital art generally do not store the file on the blockchain due to its size. The token functions in a way more similar to a certificate of ownership, with a [[web address]] pointing to the piece of art in question, making the art still subject to [[link rot]].<ref name="dash"/>

=== Environmental concerns ===
NFT purchases and sales are enmeshed in a controversy regarding the high energy use, and consequent [[greenhouse gas emissions]], associated with blockchain transactions.<ref name="Calma">{{Cite web|last=Calma|first=Justine|date=2021-03-15|title=The climate controversy swirling around NFTs|url=https://www.theverge.com/2021/3/15/22328203/nft-cryptoart-ethereum-blockchain-climate-change|access-date=2021-04-15|website=The Verge|language=en}}</ref> A major aspect of this is the [[Proof of work|proof-of-work]] protocol required to regulate and verify blockchain transactions on public networks, which consumes a large amount of electricity.<ref>{{cite journal |last1=Krause|first1=Max|last2=Tolaymat|first2=Thabet|title= Quantification of energy and carbon costs for mining cryptocurrencies |journal=Nature Sustainability |date=2018 |volume=1 |pages=814 |url= https://www.nature.com/articles/s41893-018-0152-7.epdf?sharing_token=ogrkYYbTeyhxNtpO8VyD8tRgN0jAjWel9jnR3ZoTv0NdJEcpPQZqiP9V_5sRM6OFxFiXIrEiqGJgeMqL0bBy3oWWhgCPavrJMPApmX-akgSr_A5uSnPnPPEknP0vEMNn0cVObPWp1NK2O3ttOyulWBx5GKIPbWG95X0V8tpJk9M2Z4q-wzNau-UzDXnrmvGgenXNCUHI7lbX4j0i_fnP9qqMPxjbMls9G9YEFs7oL_A%3D&tracking_referrer=www.theguardian.com |doi=10.1038/s41893-018-0188-8|doi-access=free }}</ref><ref>{{cite journal|last1=Gallersdorfer|first1=Ulrich|last2=Klassen|first2=Lena|last3=Stoll|first3=Christian|title= Energy Consumption of Cryptocurrencies Beyond Bitcoin |journal=Joule |date=2020 |volume=4(9)  |url= https://www.cell.com/action/showPdf?pii=S2542-4351%2820%2930331-7 |doi=10.1016/j.joule.2020.07.013|pmc=7402366}}</ref> Estimating the [[carbon footprint]] of a given NFT transaction involves a variety of assumptions about the manner in which that transaction is set up on the blockchain, the economic behavior of blockchain miners (and the energy demands of their mining equipment),<ref>{{Cite web|last= deVries|first= Alex|date=2018-05-16|title= Bitcoin's Growing Energy Problem|url= https://www.cell.com/joule/fulltext/S2542-4351(18)30177-6|website=Joule|language=en}}</ref> as well as the amount of renewable energy being used on these networks.<ref>{{Cite web|last=Cuen|first= Leigh|date=2021-03-21|title=The debate about cryptocurrency and energy consumption|url= https://techcrunch.com/2021/03/21/the-debate-about-cryptocurrency-and-energy-consumption/|website=TechCrunch|language=en}}</ref> There are also conceptual questions, such as whether the [[carbon footprint]] estimate for an NFT purchase should incorporate some portion of the ongoing energy demand of the underlying network, or just the marginal impact of that particular purchase.<ref name=“De-Mattei”>{{Cite web|last=De-Mattei|first=Shanti Escalante|date=2021-04-14|title= Should You Worry About the Environmental Impact of Your NFTs?|url=https://www.artnews.com/art-news/news/nft-carbon-environmental-impact-1234589742/|access-date=2021-06-02 |website=Art News|language=en}}</ref> An analogy that's been described for this is the footprint associated with an additional passenger on a given airline flight.<ref name="Calma"/>

Some more recent NFT technologies use alternative validation protocols, such as proof of stake, that have much less energy usage for a given validation cycle. Other approaches to reducing electricity include the use of off-chain transactions as part of minting an NFT.<ref name="Calma"/> A number of NFT art sites are also looking to address these concerns, and some are moving to using technologies and protocols with lower associated footprints.<ref>{{Cite web|last=Matney|first=Lucas |date=2021-03-30|title= ConsenSys launches a more energy-efficient NFT ecosystem with a project from artist Damien Hirst as its first drop |url= https://techcrunch.com/2021/03/30/consenysys-launches-a-more-energy-efficient-nft-ecosystem-with-a-project-from-artist-damien-hirst-as-its-first-drop/ |access-date=2021-04-21|website=Techcrunch|language=en}}</ref> Others now allow the option of buying carbon offsets when making NFT purchases, although the environmental benefits of this have been questioned.<ref>{{Cite web|last= Di Liscia |first= Valentina |date=2021-04-05|title= Does Carbon Offsetting Really Address the NFT Ecological Dilemma? |url= https://hyperallergic.com/634236/does-carbon-offsetting-really-address-the-nft-ecological-dilemma/ |access-date=2021-04-21|website=Hypoallergic|language=en}}</ref> In some instances, NFT artists have decided against selling some of their own work to limit carbon emission contributions.<ref name=":10">{{Cite web|last=Howson|first=Peter|title=NFTs: why digital art has such a massive carbon footprint|url=http://theconversation.com/nfts-why-digital-art-has-such-a-massive-carbon-footprint-158077|access-date=2021-04-06|website=The Conversation|language=en}}</ref>

== See also ==
* [[List of most expensive non-fungible tokens]]

== References ==
{{reflist}}

== External links ==
*[https://ethereum.org/en/developers/docs/standards/tokens/erc-721/ ERC-721 Standard]

{{Cryptocurrencies|state=expanded}}

[[Category:Blockchain games]]
[[Category:Non-fungible token]]
[[Category:Blockchain and auctions]]