Near the watch thread button you can rate a story 1 to 5 stars. However after you do it gives the average rating taking into account every users vote.

My suggestion is having another set of stars appear above or below indicating the rating you have given the story. I'm aware that the current system encourages people to leave comments discussing the story and rating it that way, however I find myself reading a story on FFN then coming to DLP to leave a rating on a story who's thread has long since died (Years ago in some cases) and commenting on it seems unnecessary.

Also being able to see all the stories I've rated under a tab in the user profile section would be nice.