Saw this over on NeoGaf
A gamer walks into a retailer and hands over the game they wish to sell. This will only be possible at retailers who have agreed to Microsoft’s T&Cs and more importantly integrated Microsoft’s cloud-based Azure pre-owned system into its own.
The game is then registered as having been trade-in on Microsoft’s system. The consumer who handed it over will subsequently see the game wiped from their account – hence the until now ambiguous claim from Phil Harrison that the Xbox One would have to ‘check in’ to Microsoft’s servers every 24 hours.
The retailer can then sell the pre-owned game at whatever price they like, although as part of the system the publisher of the title in question will automatically receive a percentage cut of the sale. As will Microsoft. The retailer will pocket the rest.