1922
This still baffles me, but I guess it's good for federation?
(i.imgflip.com)
A community dedicated to fediverse news and discussion.
Fediverse is a portmanteau of "federation" and "universe".
Getting started on Fediverse;
Yes you can have the same username on different instances, similar to how email addresses work
Don't think there's an easy way to see blocked communities, but it's easy to see blocked instances with the instances link at the bottom of the page