All posts made in the Word Games forum don't count towards your post-count.
That's probably what it is.
^^Ah! I was ninja'd!
Yeah, looking at the forum statistics, Word Games are BY FAR the most popular board. Since they were originally made for fun, I'm willing to bet that nobody expected word games to become as popular as they are, so if they counted, a member could potentially stack his or her post count to ridiculously high number within a couple of weeks for 1 or 2 word posts, not pertaining to any real discussion.
Edit:
Kobuk ninja'd me too !