Had a quick look at Mastodon stats globally. 80% of all users are on less than 1% of instances. This is not federation but centralisation by another name. Unless you actively build a long tail (20% largest instances hold less than 50% of users) there's no sustainable decentralisation. It's up to you to join small or personal instances, and motivate others to do so too.
@ton I think, when I try and convince people to at least give Mastodon a try, they're a bit overwhelmed. Also, I've heard of smaller instances just disappearing, too. I'd set up my own, if I knew a bit more about server admin—and Ruby!—and had the time for it.
@ton What I'm trying to say: it's really cool that you can just do that, set up a server and hook right into the bigger network—something the silos would never allow! But it doesn't mean you really, absolutely have to. You still benefit without going all the way.
@janboddez When social relationships determine choice of instance
it ultimately means an instance for your work buddies, your sports team, your old univ fraternity, your fellow pigeon breeders, your neighbourhood and perhaps a generic one akin to a town square or favourite pub, where you can meet strangers. That either means membership in 10+ or so potentially overlapping instances, or a personal instance that connects to your different contexts with you as the center of a wheel with spokes.
Ton's personal Mastodon instance