Yeah, as someone who used to frequent car forums back in the day, one way I think about it is you might have Mazda, Subaru, Ford, Chevy, etc specific forums. And they all had subsections devoted to suspension upgrades, with a lot of content that would look really similar to someone just getting into cars. But they also met the different needs of the different communities, and had their own vibes and culture.
Now imagine all those communities could interact with each other directly, and you end up with something like what we’re getting with the Fediverse.