An Amazon spokesman declined to comment on the patent, including how soon or even whether the digital marketplace would be set up. The patent does not make clear if such a bazaar would need the publishers' permission.
The degree to which media companies are against secondhand digital marketplaces can be seen in the music industry's hard line toward ReDigi, a Massachusetts startup that allows for the reselling of iTunes songs.
ReDigi took some pains to make its approach as friendly to the music companies as possible. For instance, any money gained from selling songs must be spent on new songs. And ReDigi says its system, like both Amazon's and Apple's, allows for only one copy of an electronic product to exist at any one moment.
Capitol Records nonetheless sued ReDigi for copyright infringement in a New York federal court, and asked the judge to shut the service down through a preliminary injunction. The judge declined. He is expected to rule on the merits of the case shortly.
An Apple spokesman did not immediately return a message seeking comment on the company's patent application, which was first reported on Apple Insider. Apple, which has not sued ReDigi, declined to comment on the court case.
John Ossenmacher, ReDigi's chief executive, said he was heartened by Amazon's resale patent.
"Amazon is pretty fearless, which bodes well for the consumers of digital goods." And, he added, for Amazon itself. "What better value to give an Amazon customer than to say, 'Buy your book here and then later you can resell it'? You can't do that with Barnes & Noble's Nook."
Free ride for Silicon Valley
Robert Levine, author of "Free Ride," an account of how Silicon Valley rose to power by plundering the traditional media companies, said he believed there was a cultural imperative to loosen the restrictions on digital entertainment; but not too much.
Before the Internet, he pointed out, there was little controversy over secondhand stores for books and music. "It never threatened the broader market because it simply wasn't that efficient," he said. "You couldn't always find the book or CD you were looking for."
Amazon, which caused an uproar with writers and publishers when it started selling used books in 2000, made it as easy as clicking a button. "Digital resale would change it even more," Levine said.
Markets usually move toward a solution both sides can live with, he noted. "But that happens slowly, and in the meantime we're in for one hell of a fight."
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