I imagine users go poof. Are their profiles stored in other federated instances? Is there a way to recover them or “import from backup” onto another instance?
If they don’t have an e-mail I imagine you can’t even notify them or authenticate them elsewhere so this “import from backup” even if technically feasible (idk if it is) would be impossible in practice due to authentication issues.
And communities, can you even notify all your subscribers to move to the “backup community” on another instance? I saw yesterday that a Mastodon server host said “I’m deleting this instance in 2 days” or something like that and I started wondering how shit would go on Lemmy.
I run my own instance and I can reply, make new posts, and even moderate communities on any instance I follow, and that doesn’t block me instance from joining. The only thing I cannot do is create communities on other instances.
So when lemmy.ml went down do to server load I had no idea until i clicked a direct link to it. I could still see my copies of their communities.
It’s more like my account won’t ever be deleted if the sever I signed up on goes away.
It will be interesting to see what happens as large instances grow and how they deal with storage and bandwidth. Any media a user uploads anywhere is hosted on their main instance. Self hosting also puts me in control of my upload media.