@pessimism It's a little complicated, but basically, when you make a post on a Mastodon or Gnu Social instance, it'll get sent out to other instances, or "federated", and users on one instance can communicate with users on other instances without the need to register on those instances (though exceptions apply, like then an domain is blocked by an admin).
@pessimism Awoo, however, is configured a bit differently. It only federates to and receives posts from Mastodon.social.
@TrollDecker Awesome, I think I grok it now, cheers.