There is a Swedish movie review site (http://filmtipset.se) which gives you a predicted rating determined from your previous reviews. They are venturing into books and wine, using the same algorithm. Unfortunately they seem to be better mathematicians than web developers, so all of their sites are pretty crappy and they seem to have problems with monetization.

Another problem is that if your taste is not really mainstream, you have to rate quite a few movies to get accurate predictions. After I reached a couple of hundred movies, the predictions were nearly always completely accurate.