This is interesting. Cory Doctorow's book, Little Brother has been on the bestseller list of the New York Times for four weeks in a row. The book is released under a Creative Commons license, which means that you can download and read it for free. If is is available for free, why would people buy it in the bookstores and send it to the NYTimes bestseller list?
Cory is a great guy and a wonderful speaker on the subject of Creative Commons and open content. I heard him speak at the first Red Hat Summit in Nashville in 2006. At the Summit, he explained that, as an author, his biggest problem was obscurity and that releasing his books under a Creative Commons license helped him overcome that.
At that time, I thought that was an interesting explanation, but this is excellent proof of what he said two years ago! I'd encourage you to listen to his 2006 talk at the Red Hat Summit and recommend that you download it in the OGG format, which is an open format.