One day, social networking will slay advertising.
The truth about products and the truth about the practices of the companies producing the products will be common knowledge. One day, if a company tries to privatize the water supply, society will quit buying their products.
If companies moderate their social networking presence, for example by deleting all of their negative reviews, then a new node will appear on the network for consumers to become aware of the truth.
We won't turn to commercials to decide which brand of automobile we should drive or laundry detergent we should use. It will be common knowledge which product is the best and which company has the best practices. We all like confirmation that we've made the best choice. It won't be long until that extends beyond product quality into business practices, now that we're all connected.