[mpeg]

The idea that people put the URL in the blockchain is misleading and people keep repeating it as a mantra.

Yes, you put a URL on the blockchain but it's almost always a URL to the ipfs protocol e.g. ipfs://QmVc6zuAneKJzicnJpfrqCH9gSy6bz54JhcypfJYhGUFQu

This identifier is a base58 encoding of a sha256 hash that points to the content. It doesn't actually tell you what host to use to find the content, that's completely left to the client app; so you could use an ipfs gateway like cloudflare-ipfs.com or ipfs.io or you could, imagining a future in which ipfs is not used anymore, use any other kind of p2p network to find the content.

Just like gnutella, or torrents, as long as someone out there is hosting the content it's usually possible to find it.

[neop1x]

Except ipfs content disappears if no one is pinning it. And you can find IPs of hosts which are pinning it. Yes there is FileCoin but there are minimum and maximum file size and contract duration limits. So someone has to periodically check pins, contracts and keep purchasing new FileCoin contracts to keep it online.

[mpeg]

Yes, true, I don't think ipfs is meant to be censorship-resistant though, so finding the IP of hosts doesn't seem like a big deal for the project goals.

My point was more that the NFT metadata itself could still be usable x years in the future when another protocol has replaced ipfs – it would just have to make the files findable by the existing hash.

The biggest potential risk would be if sha256 becomes broken and finding collisions is trivial.