As Lemmy is federated but not fully decentralised, continuation of communities hosted on a dead instance is not currently possible. (Compare this to Matrix, where a room can carry on even if its original homeserver dies, so long as at least one other homeserver participates in it.)
So that is indeed still a problem here, although not as severe, because I think the posts in those communities will still be available on instances that participated in them. Such communities would be forever frozen, though; carrying on from where they left off would require migrating to (or creating) communities on still-running instances.
Lemmy does allow you to export your own data and import it into another instance. That includes settings, subscriptions, and links to saved posts/comments. So I guess maybe you could save your own posts, export your data, and import it elsewhere to keep links to what you wrote on the dying instance. I have not tested this to be sure.
As Lemmy is federated but not fully decentralised, continuation of communities hosted on a dead instance is not currently possible. (Compare this to Matrix, where a room can carry on even if its original homeserver dies, so long as at least one other homeserver participates in it.)
So that is indeed still a problem here, although not as severe, because I think the posts in those communities will still be available on instances that participated in them. Such communities would be forever frozen, though; carrying on from where they left off would require migrating to (or creating) communities on still-running instances.
Lemmy does allow you to export your own data and import it into another instance. That includes settings, subscriptions, and links to saved posts/comments. So I guess maybe you could save your own posts, export your data, and import it elsewhere to keep links to what you wrote on the dying instance. I have not tested this to be sure.