Found this site or guide or whatever you want to call it about running a small social network:
https://runyourown.social/

While I don't think the technology side of it is that interesting (I mean, Mastodon is cool and all but there's not much to discuss there) I think what they have to say about the merits of running small communities and keeping them small is really interesting.

It feels like Discord in particular has brought back an Era of small online communities with how easy it is to just Create something and roll with it and I'm really hoping the trend continues and we see more of that kind of community all over.

The big mega communities have their uses, of course, but its a shame for a long while they were pretty much the Only thing for some people. (And thats not to say small communities are without flaws either)

My first community was a small-ass community of like max 15 people. It was a really good and fun time.