I migrated from reddit like a lot of folks. I’m using kbin.social, but it seems I can also see posts from people at places like lemmy.world. How many different instances are there? How does the federated model work? So far I like what I see, but I’m also just trying to understand how things are integrated here.
Instances are like subreddits where the mods are top level admins, and there is no central admin above them. Anyone who wants to create an instance can host their own server. Communities can be duplicated between instances so you could have dozens of c/gaming communities rather than a single community for a topic which stifles engagement a bit. The cost of hosting is paid by the admins of an instance or by donations. Sponsors and ads are not currently feasible.
Unmoderated instances allow any new instance’s content to be displayed for their users.