One of the issues I see around NFTs is simply a misunderstanding of what they are at a fundamental level and the constraints which exist. The lack of understanding is causing hyperbole and flat out mistakes in online discussion around the topic.
Some truths:
* NFT is simply an idea; non-fungible token. The idea is that of a certificate of authenticity.
* The most prominent implementation of the NFT idea is the ERC-721 standard on the Ethereum blockchain.
* The ERC-721 standard simply defines a common interface for verification of ownership (validity of the certificate of authenticity) and transfer of ownership - https://eips.ethereum.org/EIPS/eip-721
* The ERC-721 standard allows for a token to be purchased in one market place and sold in another. The same way an email can be sent from a gmail server and received on a proton mail server.
* The ERC-721 standard allows any party to verify that a given Ethereum address (wallet) owns a particular token. It allows anyone with the private key of that wallet to verify their ownership of the wallet and therefore the token.
* The private key can be shared with anyone in the same way a physical certificate of ownership could be replicated and shared with others given sufficient resources to perform the replication.
* The underlying implementation of an ERC-721 compliant smart contract (think token owner registry) is up to the developer. The simplest implementation would be an array of Ethereum wallet addresses where each index of the array represents an individual token and its corresponding value represents the owner. Just a lookup.
* If the ERC-721 standard is being followed then there is only a single "owner" of the token. Multiple owners are not supported by the standardised interface.
* Other standards exist and will likely be created in the future. Their success will be determined by network effects.
* A different NFT standard to ERC-721 COULD assign value of a single token to multiple owners. I would argue that this token is no longer an NFT :shrug:
* NFTs are not JPGs, GIFs, tickets, or pointers to an owned item. They are simply some kind of ownership entry in a smart contract stored on a trusted ledger (the blockchain). They're collectibles in the sense that a wallet can collect them.
* The value of an NFT lies solely in the external value assigned to an individuals ability to verify ownership of the token through a private key. For an art piece this might provide access to an exclusive real world event, the ability to hang the art piece in a virtual world, bragging rights etc.
* The external value can change over time. Right now you may "own" a GIF but in ten years time the artist may host an exclusive event and invite token holders.
* The standardised interface means that anyone can assign value to a given token. A cryptokitty is minted by dapper labs but can be used in any environment which recognises the token as a "thing". For example this could be a virtual world or any number of games.
* A new platform can sort of bootstrap liquidity by supporting an existing type of NFT (e.g. cryptokitties, punks etc.). One of a new MMORPG's value proposition may be that they have integrated hundreds or thousands of popular types of virtual items to be used within their world.
* As such, Dapper Labs could go bust and disappear but a cryptokitty could have value in other environments beyond this event. The standardised interface means that a cryptokitty can continue to be bought and sold beyond the lifetime of Dapper Labs.
* NFTs cannot be copied, replicated, cloned. Private keys can be shared and therefore access to the NFTs value COULD be shared.
* Based on the above points, hopefully it's clear that a given NFT cannot be minted multiple times. If the artist mints three NFTs then each one is unique. Each could have different external value assigned to it (or the same).