The article doesn't confirm that Amazon is actually planning to sell used ebooks, only that they were awarded a patent to do so. I hope that they do facilitate this someday — the lack of resale value with digital goods is concerning — but how could it be in their interests to do so? Anyone care to play devil's advocate and explain how this could lead to increased revenue over only selling new ebooks (which presumably they get a significant cut of)? I want to believe.