So I just finished a Kindle book, and this is what I saw as the last page:
They allow you to rate the book, which also includes the ability to send your rating as a Tweet or Facebook wall post, to which Amazon of course adds a link so others can find the book. On top of that they show you five other books that may interest you, based on the title, and a few more, based on the author. The only mistake in this page is that I own one of these books offered to me. I am sure that it won't take long before Amazon corrects this very small mistake and make this page 100% customized to each and every reader/customer.