Feeling kind of conflicted about the prospect of relays deleting old content. On one hand, that's kinda how Mastodon handles old stuff in order to keep storage requirements down, on the other hand, Nostr is supposed to be immutable, and if it's just like Mastodon, and only keeps your data if you pay

Well, friend-o, I'm paying for a Mastodon server, so what would then be the difference?