It all started in 2017 with colored coins on the Bitcoin Network, then got very popular with the famous CryptoKitties on Ethereum.
Adoption and Key Figures¶
The number of NFT Smart Contract rose from a few dozen contracts published every month in early 2018, to 2000+ per month by the end of 2019. See figure "Numbers of NFT Contracts on Ethereum" in this article by OpenSea.
In January 2020, OpenSea estimated the secondary market for NFTs to $2–3M USD in volume per month. Whereas now (October 2020), nonfungible.com estimates it to $10M.
While most of the experiments in NFTs have been in collectibles and games, other use cases are rapidly emerging such as Intellectual Property, Decentralized Naming Services and Ticketing Services.
Existing Standards for NFTs¶
The existing standards for NFTs is essentially divided in two: the Ethereum based standards versus the rest.
Ethereum has numerious advanced standards architected to various use-cases such as ERC721, ERC-1155 and ERC-994. Whereas other blockchains only have one or two standards at best.
The Ethereum NFT standards have a lot traction and are in real use whereas the other standards are only nascent and starting to be used.
For more details, see our Existing NFT Standards page
Existing Standards for Metadata¶
This field is still nascent with only a few standards in place. OpenSea was the first to establish one, for Ethereum. And recently (October 2020), Tezos received a proposal for Metadata Standard.
Metadata can be stored on-chain or off-chain, depending the needs of the project. Currently on-chain storage limits the size of the metadata recorded as Ethereum and other blockchains were not designed with large files storage in mind. Metadata included is arbitrary to each project so the choice of storage depends on the size of the data being stored, typically storage is on-chain if the info is very light - i.e. only text - and on a self-hosted or cloud server otherwise.
For more details, see our Existing Metadata Standards page