Yeah. Each instance is able to run their local communities how they want. Basically each instance is it’s own thing with its own rules and subs (communities). You can join that instance by creating an account there and your settings, saves etc will be maintained there.

You can’t use that login to log onto another instance, but your posts and any communities on that instance are shared with other instances so people on other instances can see your posts. The other instances don’t know about you directly, but since your instance name is there in your account name e.g. MoonKitten@lemmy.world, an instance knows it can go ask lemmy.world about MoonKitten to get information.

tldr; accounts only work on the instance you signed up on, but instances talk to each other and exchange posts, user info etc.

[–] tbe@lemmy.world 16 points 1 year ago (1 children)

Ah, so I’m basically posting into foreign communities through my home-instance :).

[–] MoonKitten@lemmy.world 12 points 1 year ago (1 children)

Exactly. If you select ‘local’ you’ll only see local communities but you’ll see other’s posts and comments on there. If you select ‘all’ you’ll see communities from all federated instances. The instances just share stuff between themselves as long as their federated. If there is a ‘bad’ instance then your local instance might decide to not federate with them.

[–] tbe@lemmy.world 15 points 1 year ago (1 children)

What would be nice is when instances could merge their communities so there aren’t many dedicated duplicates, like I could imagine there are for example LEGO-communities on 7 instances and the according owners of those communities could initiate that they want to merge with others so everyone can post wherever they are but have a common community-feed.

[–] MoonKitten@lemmy.world 7 points 1 year ago

Agreed, tools / protocols for merging communities or migrating them and user accounts between instances would be good. But it's a nice start and I like that it seems like it's going back to the old days of services like email, usenet and irc.

[–] hinterlufer@lemmy.world 1 points 1 year ago

What happens if a certain instance goes down? Is everything posted by this instance then gone? Can there be duplicate usernames across different instances? What about the email address you need to provide during sign up? Does is do anything?