It wasn’t very clear before how the new Xbox would work with used games, but it seems like the editor of the Official Xbox Magazine, Jon Hicks knows. In a tweet he says that when you sell the game, the person buying it will install it on their console which will then de-activate it on yours. This means that the used game industry is still alive, but sadly you won’t be able to lend your games to your friends for the weekend.
On second hand games: you buy disc, it installs, you play from HD. Sell disc, it installs to new console and deactivates your install.
— Jon Hicks (@MrJonty) May 21, 2013