Imagine picking up a new game, and spending hours playing it on your couch. Then, maybe your couch is occupied by other people watching movies. Well, you have a perfectly good PC in the other room, so you go fire it up, and continue where you left off. You don't have to worry about buying another copy, or setting up streaming, it just works. This is a future that Microsoft is looking at making a reality, though not everyone is happy about it.