It’s interesting, but you actually do have to scale to the 7-9 range to see the true range of values. I can’t find the paper at the moment, but this blog post describes how IMDB’s choice of having too many rating options ends up causing less deviation and skews towards the high end: http://ezinearticles.com/?Using-Smaller-Response-Scales-in-Online-Surveys&id=3442219
