For the 2006 holiday season, Sony wanted a viral marketing campaign for the PS3. Marketing company Zipatoni created a website at AllIWantForXmasIsAPSP.com that purported to be by two young geeks who created a dorky rap video to persuade their parents to buy a PS3. Then they put the video on YouTube and started posting links, talking up the video on gamer sites like Kotaku.

The goal: to persuade teens lusting for a PS3 to forward the video far and wide. The actual result: a lot of ill will toward Sony among gamers who immediately recognized that the campaign was anything but user generated.

"If you're providing an experience people believe to be innocent, not manufactured to sell something, and then you lead them to that moment of recognizing that it is associated with a brand, it's a fine line to walk without annoying or disenchanting them with the brand," Steve Peace of Carat Fusion said. "When they work, they really work, but when they don't, it can be a PR nightmare."