And you thought Facebook was just for getting a date! Stanford Professor BJ Fogg, who is writing a book about the psychology of Facebook, believes the social networking platform is revolutionary because it takes the dynamics of one-to-one persuasion and scales it up to millions. He explains why this changes the whole game of politics and business, why marketing as we know it will cease to exist, and why the notion of a target market will become perpetually beta.

Why study the psychology of Facebook?

I've long been interested in how technology can persuade people and how it can change people's attitudes and behaviors. Facebook has emerged as, I think, as the most effective persuasive technology ever.

You think Facebook is the most powerful persuasive tool in human history -- including radio, telegraph, TV, and all those other things?

Facebook is the precursor of something I'm calling mass interpersonal persuasion. That is a new phenomenon and the most important thing to happen in the world of persuasion since the advent of the radio over 100 years ago. Radio changed the game for persuasion because it allowed a message to be broadcast to thousands and millions of people, which was previously not possible. TV was an extension of that, but I don't think it was the big leap that radio was.

Facebook takes very strong interpersonal influence dynamics -- the way people persuade each other face-to-face in small groups with peer pressure, reciprocity, flattery -- and allows those to be used on a mass scale because your social networks are built in. Friends influence friends, who influence friends, and that keeps rippling out. They can reach people very quickly for very little cost and ordinary people can set these in motion. It doesn't require a big broadcasting company or a big PR campaign. If you get the right message in the right way, you'll effect millions of people. Facebook has been the best platform for that, but I think in the future it will be commonplace.

Couldn't you say the same thing about other platforms like MySpace?

I think the other platforms will get there. I think Facebook is leading because it has a high trust culture. Unlike MySpace, where you can be linked to people you don't know or find out they may not even be real people, in Facebook you generally know them or you have some certainty they're real people. Persuasion hinges on the credibility of the source. The advantage of Facebook is the source credibility is very high.

What's an example of Facebook as a persuasive force?

In the political sphere, you have the fairly prominent example last fall of a group rallying support and raising awareness for the Burmese monks. I have to admit, once I saw that come across my newsfeed -- and I saw seven of my friends had joined the group -- I really woke up to that issue and started noticing it in the newspaper.

How do you see these persuasion dynamics playing out in business?