Listening to a podcast (old) and got pointed to The FreedomBox, which intends to provide anyone willing with the ability to host their own social media. Right now, you can pick the T place or the F place, most people do. I stuck with T, but I'm no longer F-ed.
Back in the 1990s, I used to run a BBS. Certainly had its good points, and some of the offline messaging was quite frankly more useful and usable than the current web forum horrors. This ain't that. Looks like it tries to replicate the commercial services (which has been done elsewhere) with all their attractions, and most (though not all) of their flaws.
I could buy one pre-built (looks to be about eighty bucks), which'd be nice and simple. Could download the package and install it on that laptop I use as a general-purpose server machine, someplace to park all the stuff I don't want on my main machine.
Or I could track down whatever remaining BBS software there might be. I remember finding some, years and years ago. But that doesn't do much unless there are other BBSes to connect to. Most of the message content on my BBS came via some BBS nets from other systems elsewhere in the country / world. And that's not liable to be much anymore.
I do like the idea of having my own home base, though. Assuming I can come up with the eighty bucks.