This is probably going to be really hard to do, but back in December/January there were some that wanted to hit a 1,000 or 2,000 posts. It generated a lot of posts that had only a smiley, a "+1" or "+1,000" etc. There was no substance to the post.
I would suggest that a post count towards the poster's total only if it contained so many characters. Better, if it contained a complete thought. I just don't think posters should get credit for cheap posts.