I have separate accounts on each thing, but it might still be cool to be able to cross comment. Instead of screenshotting a post and talking about it on another platform, you could comment directly.
What I really want is to be able to use one account on a bunch of platforms. I could whittle it down to one real account and a few anonymous ones.
Maybe a fediverse platform JUST for accounts? The user page could have a bunch of tabs for each Fediverse platform that account is using.