Some interesting thoughts on e-books from a textbook industry blog:
Nine Important Trends in the Evolution of Digital Textbooks and E-learning Content
The increased disaggregation of content and the breaking up of the traditional textbook model — The movement toward disaggregated content has been seriously afoot ever since iTunes appeared and we started talking about songs instead of albums. We see this happening increasingly in education as digital capabilities allow us to take content apart easily and remix it into new, personal/custom collections. Today, we still think of the “disaggregation” of textbooks as breaking them into chapters. Within five years we will see all learning content as disaggregated learning pieces that can be reassembled as we want/need.