More than ever, readers are turning to used books. The increased popularity of online shopping venues such as Amazon.com and eBay is fueling the boom in used book sales.

Convenience is another reason why consumers are turning to online bookstores. Special orders produce just 1 percent of sales at brick-and-mortar bookstores, due to the inconvenient, time-consuming ordering process. For example, economics researchers from MIT ordered the same book at a Barnes & Noble superstore and through its online store, bn.com. The purchase at the brick-and-mortar store took nearly an hour to place, cost $37.45, and took eight days to arrive. By contrast, the online required just three minute to place, was delivered in three days, and was $5.46 cheaper. And don