I stumble by accident on this fascinating story by Garth Hallberg first published in Slate.com last January.

In it, Mr. Hallberg goes about peeling off the veneer of Amazon's Top reviewers. A knowledge that he acquires first hand as he follows minute by minute the progress of his book's rating on Amazon,
A Field Guide To The North American Family.

I know very little about Garth Hallberg, except for the fact that I've since realized that I heard him read a fantastic story at the May 29 Literary Death Match. But that limited knowledge of him makes me trust every word HE writes.