Add a live chat app to each movie or episode screen so that anyone who has checked in can jump into a live chat on what they are watching.
This would work much better if there was more pre-adding of episodes, before the episodes actually aired. Perhaps you could link up with TV guide or get show reps from the studios to pre-enter their information. They would have the incentive as a route for hyping up their shows while ensuring that the correct information is on the site. This is quite novel and while the tracking is great, the ability to live chat while watching would be something like live Tweeting while you watch an episode. Perhaps you could # tag add a Twitter live feed to the Miso page. Again, just a thought. Social interaction while watching my favorite stuff is fun and desirable (in my opinion).