The Smartphone and TV go hand in hand.
This is the main reason why Twitter is the real winner for TV multitasking, not Get Glue, nor Facebook.
People want to get news and converse in real-time about the shows they’re watching.
You can chat on Facebook in real-time by following the ticker but there’s less chance that your friends and people of interest are using Facebook to talk about the show.
People, especially mobile users, are getting used to more public social networks like Twitter. They may not produce content but they will certainly follow Twitter like an RSS feed.
The thrill of catching a good tweet while watching live television is more powerful and more buzz-worthy than a Facebook ticker post.