"Amazon needs to do everything it can to reaffirm its relationship with book publishers," Weiner said. "By saying it has sold more e-books than paperbacks, Amazon is telling publishers that there a lot of e-reader devices out there, and there may be a lot of noise about iPad and what Barnes and Noble is doing, but we're the company to beat and we own this space."

Weiner said Amazon is "seemingly a huge power in publishing, but last year a number of companies started nipping at its heels, including Apple." There isn't a lot of profit in selling paperbacks, Weiner said. By noting it sells more e-books than paperbacks, Weiner said Amazon seems to be telling publishers and investors: "We still own this space, and not Google or Apple."

Matt Hamblen covers mobile and wireless, smartphones and other handhelds, and wireless networking for Computerworld. Follow Matt on Twitter at or subscribe to . His e-mail address is .

in Computerworld's Mobile and Wireless Topic Center.