People have tried over the years, but it's easy to.get lost in the sauce with the crypto and then you're babbling about Byzantine generals and stuff

you are literally in it. that's what federation is supposed to be.

Check out Reticulum. It's a full-blown decentralised network stack, so you can chat with someone not even using the Internet and instead employing a LoRa radio or a HaLow modem (but you can use both at the name time!). Every user is a client and a server at the same time, kind of like bittorrent, but actually decentralised on o much deeper level.

You're in it! each 'peer' is a Lemmy instance. The only reason everyone doesn't have their own instance for themselves is that it's too complicated for the average person to setup easily, but I have seen it done before.

Isn’t a “more correct” description of BitTorrent that each client is also a server? I’m not sure exactly how the protocol is written, but I assume each connection acts like a client-server one depending on the direction of data flow. With that in mind the fediverse is distributed social media. There’s nothing stopping you from spinning up an instance on say, your phone, making an account on it and federating with the other instances you like. Now your phone is both client and server, just like in BitTorrent. This setup would even match the functionality of only seeding when on. If you turn off your instance it would go offline and any non-federated data would not hit the web until you booted it back up, aka started seeding again. Defederating would act like removing a torrent from your list. Multiple users per server is where I think the analogy begins to break. Not sure what the BitTorrent equivalent would be.

Edit: Maybe SoulSeek is a better parallel??

Nostr and plebbit are the closest I can think of, the latter uses IPFS so is completely decentralised.

Sounds like you're looking for nostr? Lad time I checked there was nothing but cryptocurrency spam.

P2p mesh?

This would be more of a use case for blockchain, any site(/user) wishing to mirror the social media would participate in the chain. A post on one site would get pushed into the chain and show up on every mirror.

Media would likely have to be links outside of the blockchain since it isn't usually very good at storing large datasets (it would make it difficult to mirror over time as it grew), so if you wanted a full mirror you would probably have your site fetching media as soon as it is posted and mirroring it yourself.

Or media might be a good spot to integrate with your bittorrent idea. Blockchain handles the distributed state of the site (communities/post text+metadata), and any submitted media is added to the post as bittorrent hashes. I don't know how scalable bittorrent clients are though it might take considerable overhead to seed millions of pictures/videos.

Meshtastic with mqtt (maybe?)