UK citizen, Chris Read, is facing legal action after leaving negative feedback on eBay. Chris purchased a phone from the auction site, but when receiving the phone it was the wrong model and wasn't in the "good" condition described by the seller (scratched and chipped). After leaving an honest and non-threatening feedback response, Chris was contacted by the seller with a legal notice threatening a court case for libel. While the buyer's comments were honest, the seller claimed that he was hurting the store's reputation and its ability to trade and make money.
Obviously, the seller handled this wrong. Instead of blowing up at the honest buyer when they were the ones at fault, maybe the seller could have used the mistake to go out of their way to fix the problem. A few years ago, I bought a CD online (Amazon I think) and received the wrong edition compared to the one advertised. I sent a message to the seller, who immediately apologized for the problem, and refunded me for the purchase, but let me keep the album for free. Sure, it wasn't the exact product I wanted, but I was satisfied by how the seller handled and made right the mistake.
There may be two lessons to learn here. 1.) We have a choice how we handle feedback. How we react can isolate our customer further, help us improve our product, or even surprise them in a good way that would make them want to tell their friends. Everyone knows that bad service is passed along seven times more than good, but never underestimate the power of surprisingly good service. 2.) The market is free to comment on your performance. It is important to let ridiculous and unfounded claims blow over. Truthful comments - especially when negative - will provide the greatest and most valuable insight to your brand, but only when handled properly.