That’s more bittorrent that federated, but maybe the metadata could be federated. It would share a lot of the same problems as bittorrents though: DMCA, prohibited content, content that’s no longer relevant enough to be available. So not only would the federated servers have to deal with requests from law enforcement and takedown notices, but so would ISPs and its users. Imagine not being able to host a federated server of it if you don’t run an algorithm that scan for infringing content. But besides that, yeah, maybe that would be plausible.