I suspect tons of content providers beyond authors are looking at this and saying WTF? A lot of game designers have specifically moved toward downloadable content to avoid the issue of used video games. Right now, I think, there is a nice balance. I can still buy a used video game, but if I want access to all of the special content I have to buy the DLC. As a gamer, I'm cool with that. it actually increases the value of my game experience to be able to download new content for a game a bought. But I suspect game designers will scream murder if Amazon tried to sell "used" DLCs. The music industry only recently came to terms with digital content. Now Amazon wants to let people resell "used" MP3s? And what about things like apps? Movies?