@UrsulaKatS @feditips
User concentration on mastodon.social does feel like a problem, maybe a time bomb -- although it is registered as a gGmbH (non-profit/charitable LLC), so should be immune to a hostile takeover.
I haven't yet read about any solutions to offset this general problem -- like a nonprofit "Fediverse Foundation" that accepts donations to seed and guides new community and municipal instances.
When I opted to join Mastodon last month, I first reached out to a friend who runs a home instance, but they were wary of adding any accounts. I then reached out to the admin of a local server in my city, with several users I know, which had paused adding new accounts, but didn't hear back. I ultimately signed up on this instance because I have a network security background (and ongoing interest, although it's no longer my career). If I lose my footing here, I could host my own fediverse instance, although at this point in my life, it would not be worth the stress, storage space, or bandwidth.
(Several years ago, I had an account on a Friendica server, which ultimately shut down, but I had already lost interested in it, because no one I personally knew was on the Fediverse; the landscape is very different now.)