As I understand it, the reason your rating bounces between one point and the next has to do with the math used to create your "average post score".
Each time you make a new post, you add to your total postcount, but the fact that your postcount has changed means the math of averaging your overall score also churns out a number that fluctuates, particularly when you're right at the cusp between one point and another point. (I believe some rounding of numbers may be involved; also, some spinning chickens and shaving of cats may also be involved)
Either making more posts, or being quiet and getting a few solid rate-ups should stabilize it in one direction or the other.
Edited, Tue Dec 7 21:26:20 2004 by Tenmiles