@evan @anildash @paulmwatson @ummjackson @Gargron I meant more the structure that Anil is referring to - it is confusing for new users and outsiders. Even OSes think that these handles are email addresses.
I'm suggesting that if, for example, there was a landing page and people selected a user name and perhaps the domain appended to that (with terms and conditions depending on the domain selected) then perhaps it would all feel clearer and more seamless to the inexperienced user.