A contractual problem threatens the ebook business of all the major publishers.
It begins with the next big thing in book publishing: advertising.
Have you used any free iPhone apps that generate revenue for their creators by running small ads above or below the apps' primary content?
Have you seen photos of the Barnes & Noble Nook ereader, with its second, independent display that's capable of showing advertisements?
A reader spends a lot of time with a book. Ads will hav....

