Do you have thread ratings enabled on your forums? If so why is it enabled and if not why not? On ours we tend to disable the thread ratings as we dont think it is necessary at all.
I leave it enabled, but I don't see it used very often. I have found, however, that if you use a live thread rating mod (AJAX) and move the rating from the drop-down menu to above the first post, it's more prominent, easier for users and they are more likely to use it.
Only a few people really use it, and they mostly only rate their own threads (all 5 stars, of course).