Check out this amazing story in the NY Times Magazine about an eyeglasses company that has used negative reviews of its company to gain more business. No big deal, you say? I doubt you'd leave the article with the same impression. The owner commits fraud, threatens acts of sexual violence against unhappy customers, takes (and emails) photos of apartment buildings where the customers stay, and looks up phone numbers to make harassing calls. Why? Well, the answer is as clear as Google's ranking algorithm. There are so many factors, external to a website, that effect ranking and bad reviews provide a website links and references. Even if they are scathing, it helps. A company usually cares, but I guess that caring isn't universal.