Doing it on purpose
The massive marketing engines of the car industry have decided to run roughshod over the idea of viral marketing and they're working hard to manufacture ideaviruses as fast as they can:
Why does it bother us so much when marketers try to subvert the ideavirus process and buy their way into our lives?
Precisely because it feels so intentional. Because it represents an unwelcome intrusion, a display of power... it's a lot like spam, in fact.
When you run into someone with "Scion" tatooed on her forehead, it's odd. When you realize that person got paid to do it, you feel used. Maybe it's just me, but I think there's a huge difference between the famous Honda Cog Movie (or the BMW movies) and the manipulative Scion campaign. In the first cases, the car companies built something worth talking about. In the second, the manufacturer just bought the conversation.
With more than 55,000,000 downloads to date, the BMW campaign is a success by any measure. It's hard to imagine that Scion can afford to buy enough "buzz" to make a difference. If Permission Marketing is about dating, then buying these conversations is about nothing more than prostitution.
(PS what about bzzagent.com? Yes, they get paid to help start conversations. But a key part of their business model is that they DON'T pay the sneezers themselves. The bzzagents work for free. It needs to be that way for it to work, imho).
Is it a fine line? You betcha. So is dating, for that matter! The magic and the art comes in creating remarkable products that don't cross the line... they're worth talking about, but they're not paid conversations.