For everyone confused by the whole federation thing, trying to compare it to Twitter... Forget Twitter. Think e-mail. You can choose between different e-mail providers on different domains or even host your own server instance. Then you can communicate across those instances with other users on them.
No, it doesn't make sense to "claim" your nickname everywhere. Yes, you should choose the server wisely because all your data reside on that server without an easy way to migrate them...
The Ruby library for interacting with the Mastodon client API is in dire need of completion. If you're looking for ways to contribute code, I think that's a good starting point https://github.com/tootsuite/mastodon-api
A strange game. The only winning move is to federate.
(Still trying to suss out how to find people elsewhere, what's going on behind the scenes, etc.)