This explains the fediverse with some examples of different instances
https://socialhub.activitypub.rocks/t/introduction-to-activitypub/508
I joined lemmy.world, because that’s the first one I came across. But now I can see the posts from many instances using voyager and Memmy. Now you can go and join any instance with interest you. That’s the beauty of it.
No, but some people are discussing about creating new logins, so I want to clarify. Thanks for the clarification.