"'The threadiverse', aka #fediverse group servers like #guppe, #lemmy and #kbin are all based on the premise that each community is hosted on one instance, but users and posts can come from all over. So it's like any normal #phpBB-style forum, except you use your own user instead of having to register and check everywhere.
Makes sense to me, and I'm not saying that they should do it any other way, but this is exactly how mailing lists work."
