Ten years ago, I studied readers of the then popular Left Behind series of Christian apocalyptic novels. If I conducted that study today, I would potentially have access to far more objective data about readers than I did. How quickly do they read? Where do they stop reading? What passages do they mark? Do they write notes in the margins?
E-books are providing companies with the opportunity for all of this information and more about people who use e-readers like the Nook and Kindle.