I have my skepticisms about this whole thing. While I know the answer is "they will be defederated", what if one of the big ones, like lemmy.world or lemmy.ml get huge, then sell out to something like Meta?
We lost 3rd party apps and we are morning the biggest breakup we've ever had with reddit. Say the server you've had your account on for so long and all your content gets taken over by a giant with strategically placed adds that are upvoted by bot armies for visibility. They may get defederated, but that means Meta just came in and destroyed a huge chunk of users accounts while gaining some ad revenue for a bit until the community dies. Everyone has to actively pack up their shit and move to another instance. I guess the loyalty to an account is less with a lack of account karma so it wouldn't burn as bad.
You would lose all your subscribed communities when you are forced to move out. That would suck. Too bad you couldn't export like a .db file from your account on the way out and upload it to another account on another instance. Possibly some sort of encrypted key so you can auto add as a mod to any community you were modding on your previous account. No clue if that makes any sense. Kinda Like a lemmy "Go-Bag"?
I don't know, just thinking ahead of the shenanigans that's going to happen if this really starts making a dent in huge corporations user counts.