Sources: Edge , 
quote: If they can pull it off here, it won't be long before the media giants do the same for music/movies.
quote: Ever heard of iTunes, Amazon, Google Play, Xbox Live Marketplace, PSN... It's already here. Has been for a while.
quote: Paying customers to whatever chain they are purchasing the game from... the developers and publishers of said game don't see a dime from that transaction.
quote: In all events with games now being made costing much more than in the past... every used game sold in a retail venue means that the one that actually could help the company stay afloat is sitting on the shelf
quote: If MS allowed digital used game sales and paired it with the ability to log in as another live user and play a game that user has (for the whole bring a game to a friend's house scenario) this would be a non-issue for 99.9% of the user base.