@feditips User experience behind that federation is disingenuous at best: You can subscribe and "interact" from anywhere. Everyone keeps saying so, it must be true. But it isn't.
Subscribe to a kbin theads from mastodon. Now you get a firehose dump of every comment on every thread, chronologically, with no metadata (votes etc.)
If you can parse that stream, responding works fairly well.
Unfortunately, responding is not the same as actually participating. Up/downvote isn't a mastodon feature, so no voting or even seeing the votes. Same across other "federated" services.
To participate, I need a BUNCH of brand new accounts. Which part of "federation works everywhere" is that?
Off the cuff, it seems like the building blocks for account equivalency are in place. SSO + a modified account migration verification can create and maintain remote 'sessions'. That even lets my "main" server send me to a compatible remote client to do remote stuff with a simple hyperlink and OAUTH bounce.