You should be able to friend people on NetFlix, as though it were a social networking site. When you have friended someone, you can view their queues and movie ratings, and NetFlix's predictions as to how much they would like various movies. You can get the intersection of their queue with yours. You can get a NetFlix recommendation for movies that NetFlix thinks both of you would like, to help you decide on a movie to rent to see together. And (and this is the feature that first got me thinking along these lines), you can have NetFlix notify you when they send a movie to your friend that is on your queue, allowing you to arrange to watch the movie together.
I will simulate the last feature on LJ shortly by posting a list of a dozen movies I'd like to see. Friends who also want to see one of them can contact me so we can see them together.
Netflix should also partner with a dating site. If you agree to release your Netflix recommendations to the dating site, then it can use "likes the same sort of movies as you" as one of its compatibility metrics.