Bruce Schneier takes a look at various kinds of e-book fraud:
The first is content farming, discussed in these two interesting blog posts. People are creating automatically generated content, web-collected content, or fake content, turning it into a book, and selling it on an ebook site like Amazon.com. Then they use multiple identities to give it good reviews. If it gets a bad review, the scammer just relists the same content under a new name.