But is this claim legal? Our Columbia friends suggest that just because Sony or Amazon call it a license, that doesn't make it so. "That's a factual question determined by courts," say our legal brainiacs. "Even if a publisher calls it a license, if the transaction actually looks more like a sale, users will retain their right to resell the copy." Score one for the home team.

There's a kicker, though: If a court ruled with you on that front, you still can't sell reproductions of your copy, an illegal act tantamount to Xeroxing your Harry Potters. You'd have to sell the physical media where the "original" download is stored—a hard drive or the actual Kindle or Sony Reader. Our guess is that it only gets more complicated from here. What happens when the file itself resides only on some $20-per-month Google storage locker?