If you set your ratings to public, and visit someone else's activity page that also has public rating, you can see an interesting chart on how their tastes compare to yours. Here's our founder Col Needham's activity page. The page will do a Pearson Correlation between two users ratings and display a statistic about how much your tastes overlap.
Note that this feature is under development and the number could change dramatically and you should not make potentially life-altering decisions based on this rather arbitrary number. It will also display a set of films for which your ratings diverged form each most dramatically.