How many niches can eBooks fill out?

I’m not sure this will work, but I suppose we will see:

Amazon’s business model has long been dependent on resellers of used books and other merchandise. But a U.S. patent that Amazon Technologies in Reno, Nev., received last week indicates that the mega-retailer has its sights on digital resale, including used e-books and audio downloads. According to the abstract, Amazon will be able to create a secondary market for used digital objects purchased from an original vendor by a user and stored in a user’s personalized data store.

Here is a bit more, and for the pointer I thank Chaim Katz.  And here is news of a new Texas library that will offer digital books only.