If you don't know Beehaw.org defederated from us but communities from there that have a copy on this instance are still visible to Us and we can post on them, they can't see what we post or comment on those, and we can't see what they post and comment over there.
they are gost communities hosted on this sv because how Lemmy works, and my question is what will be done about them.
I know absolutely nothing about how Lemmy works but there's hopefully some way or will need to be eventually a way to remove old posts from a certain instance. For instance if there is illegal content it would need to be removed. Building a good solution for this that could be done optionally in the defederation process would probably be good and will be necessary at some point anyway.
For instance you defederate from a nazi server — you'd absolutely want the nazi posts gone from your server. And legally you'd need to potentially depending on where the server was hosted — and of course other kinds of illegal content and networks.
I'm not sure what the current state of the tools is though.