could-- more likely, I think that it won't. What's Facebook do? It helps you connect, and reconnect with friends and family -- what's that have to do with buying and selling goods? Why do I need to watch shows on Facebook, and not somewhere else?
Well, for the same reason people already do it on vkontakte.ru:
- it's easy
- if you go fullscreen it doesn't matter where you're streaming from
- it lets you discover stuff you might like (what's your friend watching, etc...)