> Just an anecdote - I never used Twitter/X, and never used BlueSky. Recently (about a year ago), joined Mastodon. I enjoy it, find a lot of value there, and have interesting conversations

Same, more or less. Twitter started as a place to be interrupted by attention-seekers, and Bluesky was just "that but with less Elon Musk and more implementation throat-clearing." I never saw the point. Mastodon feels more like old-school Usenet, where you could find communities with shared interests, block the attention-seekers, and shrug at the usual human drama.