Yes posts do figure into it a bit, but Reputation is a major contributor to the title. If you look at my number of posts compared to any of the tree previous posters, you will see that two have less and one has more posts, but if you mouse over the little green squares below the title (they represent Reputation), you will see a HUGE diffence between their Rep and mine. This is because all three of them have posted many more maps of much higher quality and have garnered much more rep for them than I have.

I hope that clarifies things for ya.