Big brands and large corporations think social media is subversive. So they should. Social media talks back, seeks to open closed networks, makes everyone a publisher, gives everyone a voice. If the message has a certain alchemy, social media makes it viral, like a snowball rolling downhill, gathering critical mass at an exponential pace to become a marketer's worst nightmare.

In the old days, people would write letters to customer complaint departments, phone consumer hotlines or whine to friends. There were even companies that did metrics about how many customers you'd lose if you didn't solve a customer complaint well or quickly enough. That phenomenon of consumer interaction was called word of mouth.