Mastodon is a bit less centralised around nodes, but there are a number of tech communities gathered around a couple of instances already (although they all int

Mastodon is a bit less centralised around nodes, but there are a number of tech communities gathered around a couple of instances already (although they all interact with each other and other instances, so it's not that big of a deal): https://hachyderm.io https://hachyderm.io, https://fosstodon.org https://fosstodon.org and https://front-end.social https://front-end.social are big ones in my circles.