Hell, even Mastodon is doing pretty well these days given Twitter's awkward struggle. It's decentralized in that anyone can run a server, but also a server is allowed to break connection with any other server they see as problematic which is great for protecting your instance's users from bullshit. At the same time, users can move from one instance to another (and their followers remain in-tact) without too much hassle. It's a surprisingly elegant design for a social network.