Post Ratings ?

I do not exactly understand how it works. One day mine is at 80 and the next it's at 155. I was at first under the impression that it was the number of post you have put up, but I guess not. How does it work?

near as i can tell, it works like this. when you make a post it goes up to the same number as your total number of posts. then it begins to decrease. if you post again, it goes back up to the total. its a good way to know whose most active.