Sony prohibits the resale of Playstation games
In the new terms of service from november, there is this line:
7.1. You must not resell either Disc-based Software or Software Downloads, unless expressly authorised by us and, if the publisher is another company, additionally by the publisher.
This rule is for PS3 and PS4 games, although they don't tell us how they are going to restrict this.
I think it's very unfair to start a shit throwing campaign against Microsoft at the E3, and two weeks before launch changing your terms of service to the same thing. I was always going to buy an Xbox One, but now I can laugh with people who laughed with me when they posted this:
Official PlayStation Used Game Instructional Video (via PlayStation)