Screenshot by Lance Whitney/CNET

Online consumers may one day be able to sell or trade their digital items to other users, at least if a new Amazon patent comes to fruition.

Granted to the retail giant on January 29, the patent dubbed "Secondary market for digital objects" describes an electronic marketplace for swapping digital items.

You'd start off by housing your purchased music, videos, apps, and e-books in your own online storage space, just as many of us do today. When you get tired of listening to the same songs or reading the same books, you can move those items to someone else's storage space. The moved items are then deleted from your own space.

Amazon's patent would impose a limit on the number of times a digital item could be transferred to another person. When that threshhold is reached, the ability to move that specific item would be suspended or cut off permanently.

The seller would receive some type of credit in return for moving the item, while the buyer would be debited a certain amount. Amazon itself would charge a fee for the transaction, which could be collected from the buyer, the seller, or both.

The concept certainly holds promise. Transferring or selling a digital item to someone else currently can be a tricky matter. Many such items are saddled with digital rights management, limiting who can use them and where and when they can be used.

"A secondary market which allows users to effectively and permissibly transfer 'used' digital objects to others while maintaining scarcity is therefore desired," Amazon said in the patent. "A 'used' digital object is one to which a user has legitimately obtained access or ownership rights (hereinafter 'access rights'), and to which the user may permissibly transfer to another user."

Amazon's patent win for this type of marketplace does open up some legal issues. ReDigi, a company that lets music owners sell used MP3s, has gotten in trouble with the recording industry over allegations of copyright infringement.