In Reading the Book: A Novel Approach to Reviewing at Publishers Weekly's Beyond the Book blog, Barbara Vey talks about those Amazon Reader Reviews that can be so very, very...interesting. This is clearly a subject that hit a nerve with her readers, since she received 59 comments.
Vey directs readers to a very recent Slate article by Garth Risk Hallberg entitled Who Is Grady Harp? on the same subject. Hallberg describes a reviewer hierarchy at Amazon and how it can be manipulated. I had a little trouble following the whole social networking aspect of the review system, but, then, I have trouble with social networking, anyway. (Ask anyone who knows me socially.)
I believe some of my reader reviews began life as book reports.
Thanks to child_lit for the link to Publishers Weekly.