Garth has an essay on Amazon’s celebrity reviewers up at Slate.
Full disclosure: It was late at night, in a fit of furtive self-Googling, that I discovered the first Amazon customer review of my debut book of fiction. “Superb,” wrote Grady Harp of Los Angeles. “Fascinating … addictive.” Not to mention “profound.” Such extravagance should have aroused suspicion, but I was too busy basking in the glow of a five-star rave to worry about the finer points of Harp’s style.