No need to brag about the most pages indexed on the web, when you have unique off web content like Books that you can index and search. I think Amazon has a better plan because I think they will leverage their book reader and, at some point, sell digitized books via their Reader instead of purchasing hard copy books.
E-Commerce News: Publishing: Google Settles Book Search Suits for a Song: “‘They’ve got to get the pages up and see what kind of page views and revenue it generates,’ he said. ‘It won’t be on the scale of paid search or anything like that. This is old, historical content. It’s a niche play. It’s a completeness-of-the-index play.'”