According to an article in Slashdot, Amazon wants to patent the idea of inserting advertizing into eBooks and other online generated content. One example given is that if a restaurant is described on a page, the preceeding or following page will have an advertizement related to restaurants or dining.
This reminds me of the fad for blow-in (or worse, glued-in) ads that were popular in trade paperbacks many years ago. (If I recall correctly, they were 90% cigarette ads.) They were made of much heaver stock than the regular pages and thus acted like unwanted bookmarks. The first thing I’d do would be to shake or rip them out. Arrgh.