From a New York Times story:
The weeklong glitch, which Amazon fixed after outed reviewers complained, provided a rare glimpse at how writers and readers are wielding the online reviews as a tool to promote or pan a book–when they think no one is watching.
John Rechy, author of the best-selling 1963 novel “City of Night” and winner of the PEN-USA West lifetime achievement award, is one of several prominent authors who have apparently pseudonymously written themselves five-star reviews, Amazon’s highest rating. Rechy, who laughed about it when approached, sees it as a means to survival when online stars mean sales.
Read the whole story at CNET.