I forget the titles, but you get one star (and a new level) on 50 posts and another start (and a new level) when you make 100 posts. As Hal has hit 150 without gaining another star, I'd guess you get your next star on 200, then probably on 500. I guess if you download and read the snitz code it may tell you how the stars and levels are organised, although this may be dependant on the implementation.

regards
David Cameron