Video sharing? Audio? GIFs?
Replies? Discussions? Groups? DMs and PMs?
Who is your audience? People who can install Docker? Or people who don't know the difference between a browser and an "app"?
Look up and read about XMPP, Matrix, and ActivityPub. Here's a document:
https://docs.joinmastodon.org/
That talks a little about the protocols and the software and might serve as a reasonable starting point.
Audience: a Docker audience suffices.
Maybe you want a Mastodon instance that specialises in your sort of thing, and allow federation to catch the people who have interesting things to say, but are on a different instance.
A federated Mastodon-like instance might be the move, but I have a way of providing Sybil resistance so could probably have an open p2p relay network. This is why I was asking for reading. I want to make sure I understand all the options.
For more context, I want to decentralize https://stacker.news which is basically an HN clone with Sybil resistance (costs bitcoin to post/broadcast) and karma is withdraw-able as bitcoin. The community is very fond of decentralization for obvious reasons plus I think it'd be a fun challenge.
I'm waiting to hear from the rest of HN, I've been curious about decentralized websites for a while.