Amazon.com has filed for a number of patents that hint at ad-supported books for its Kindle e-reader--more specifically, a free or discounted ad-supported e-book for customers who buy the physical version.
Amazon Technologies, a subsidiary of Amazon, filed for a patent ("Method and system for access to electronic version of a physical work based on user ownership of the physical work") in December 2006. It was approved last month and makes it possible for buyers of a physical book to have an e-book bundled with it.
But two additional patents, filed a year later by Amazon employees (and not yet approved), are the more interesting ones: these, according to MediaPost, "clearly note that Amazon would insert advertisements throughout the e-books, from the beginning to the end, between chapters or following every 10 pages, as well as in the margins."
It looks like the story first surfaced on Slashdot last Friday.
Presumably, this could be a way to guide potential Kindle customers through the transition--which some find daunting--from , subsidizing the price of either or both of them in the process.
Ad money would be an additional revenue stream for Amazon too.
This post was updated at 10:14 a.m. PT.