I'm a longtime Twitter follower of British spy thriller author Jeremy Duns, a former journalist who has helped uncover high-profile, recent incidents of plagiarism (Q.R. Markham, Lenore Hart) and "sockpuppetry" i.e. creating false Internet IDs to praise one's own work or arguments while bashing those of fellow authors.
As a nerd, goody-goody, and teacher, the thought of creating sockpuppets never occurred to me. I imagine if I did, I would be quickly caught. But I have dealt with a sockpuppeteer in my time as a discussion list moderator.
A member of Spenser's Sneakers calling himself Spensermein created three IDs to support his arguments. I traced the IDs to the same IP address and banned them all. It's sad that people feel they need to support their points in this deceptive way. I imagine it's more difficult to trace and stop fraudulent reviews on bookstore sites, but I hope the work of Jeremy and others exposing sockpuppets will encourage higher standards of site security.
Every work is bound to get a bad review sometime. Authors responding to them personally or driving their fan bases to Amazon seems petty. It bothers me, though, that people are allowed to rate books without actually writing a review, such as this 2-star, anonymous "review" of my ebook, Call Me Cupid, on BN.com. You would think BN's system would flag it, saying, "You haven't written anything," but evidently not.
My review policy is to point out a work's strengths and weaknesses without getting personal. As impersonal as sockpuppetry pretends to be, it is extremely personal when you think of the time sockpuppeteers spend crafting their false identities to put others down to an extent they never would using their "real" names. Sockpuppeteers actually take reviews of their work very personally and can't stand the thought of many readers preferring someone else's work.
By the time writing or any product is made available, creators should have developed some objectivity about its quality, so they don't take criticism personally. Before reviewing products, consumers should have developed similar objectivity, so their criticism isn't personal.