j.cammarata.art on Nostr: Can someone explain (in layman terms if possible) how things work across servers? ...

Can someone explain (in layman terms if possible) how things work across servers? Going to view posts from someone I follow at mastodon.social and it doesn't display all their posts. I can click on the link to go to the other server but can't interact in any way. Is this because the @mastodon.art server I am on blocks them in some way? I see you can switch servers but you lose all your posts. Would suck but I'm really considering it.