This will become more important as electronic books and music squeeze out physical content. How do you sell back any electronic music or books that you bought? Both Amazon and Apple are exploring methods for a marketplace in electronic content. Fearing market dominance, many people are worried about what will happen, citing the low cost of used books on the internet.

Scott Turow, the best-selling novelist and president of the Authors Guild, sees immediate peril in the prospect of a secondhand digital thrift shop. “The resale of e-books would send the price of new books crashing,” he said. “Who would want to be the sucker who buys the book at full price when a week later everyone else can buy it for a penny?”

This long article at the NY Times, covers copyrights and patents involved in such a prospect. How sad, when there is no patent involved in opening a used book store. The issue of paying royalties on used books is always a sticky one, though. But should someone have to be paid every time their content is sold and resold?