It seems like a cool idea. The idea of picking a server to sign up for didn't throw me for a loop like it does some folks; just like email, right? I think it needs a better way to interact on other instances though. Like for this one, I found lemmy.world from a link on Reddit, then opened this post. But I couldn't vote or comment because my account was on midwest.social. So I had to copy the !lemmyworld@lemmy.world community spec from the sidebar, go over to midwest.social in another tab, click the search button, paste the community spec there, re-find the same post, and now I can comment. Ideally I'd instead just be able to comment directly on lemmy.world using my already-logged-in account on midwest.social, or at least go directly to viewing the post via my own server with one click. Functionality like this would probably require a browser extension but that's better than nothing. I actually found one for Mastodon that's supposed to allow something like this for that service but so far I can't figure out how to get it to do its thing, and I don't think it supports Lemmy at all so far.