I was quoted this week in a Canadian Business magazine article called 'The Taming of the troll; Everyone's a critic, especially online. So what's the best way to deal with bad reviews?' by Deborah Aarts. The article is only in print at the moment. But here's a link to the publication's home page in case it gets posted in the future.
My advice, among much else that of course didn't make it into the article, was essentially to stay cool.
"Never react to a bad review with anger or emotion. If you attack your critics online, they'll just attack back-and they'll almost always win. It's preferable to respond with accountability. Also, if the situation is appropriate and if your company is comfortable with it, a sense of humour can be a marvellous way to respond to critics. Research shows that humour is one of the key drivers of virality on the web. People love it."