@sod And now I've taken a look at that site, and I can see it's one that I need to spend time with. A couple of points jump out at me: Mastodon is huge; everything else in the fediverse is nearly a rounding error. (And that's fine for people who are into those platforms, as I am with micro.blog.)
Also, Lemmy seems like it's worth taking a look at. It seems to be a nice size. And, while I have enjoyed Reddit in the past, I'm feeling less and less good about spending time there, for multiple reasons, among them I'm feeling more and more foolish about working for free to help enrich centimillionaires and billionaires, especially when the centimillionares/billionaires are jerks.