Ja, but you need an index for each thread, some kind of time partitioned thread index for each community, same for all.
Then you need to query all comments or posts by user, so that’s another index, then you need some way of querying for hot, or controversial or what have you.
It’s doable, but fiddly. Tempted to have a go though!
There’s a few posts around about server setups that people are running. The major constraint seems to be storage. Lemmurs uploading gigs of data can get tricky to manage pretty quickly.
Bit of a pain to store in Dynamo, though. You’d need to write a bunch of different views, I think.
One comment thread makes sense as a partition, but listing threads is going to be awkward, and search is basically a no-no.
It’d be slow, though, like a lot of the darknet protocols, and would mean that whether or not your post is visible depends on which users you’re connected to. I think the usability problems would likely rule it out.
P2P works great for filesharing because you’re reading small numbers of large things, so if each thing takes a minute or two to start, that’s fine. It would suck for reading the memes community on a social network cos you need to read many small things, and if they don’t load quickly the experience is ruined.