So, think about how you use a disc that you own of an Xbox 360 game. If I buy the disc from a store, I use that disc in my machine, I can give that disc to my son and he can play it on his 360 in his room. We both can't play at the same time, but the disc is the key to playing. I can go round to your house and give you that disc and you can play on that game as well.