It's just a kind of funny way to show how active you've been.
I have no idea where the break points are actually but it will change as you post more.
You start at 1st Kit, then Brewer, eventually you get to labels like "I spend way too much time on the AHA Forum" and Grand Pooh-Bah of no life".
Doesn't really mean except a joking comment on how often you've posted.
Paul