Facebook looks for friends in advertising

Facebook is already challenging big Web businesses such as Google and Yahoo for users' time online and for advertising dollars, thanks to its audience of more than 500m users and the information they share.

It has built a significant advertising business from social gaming, thanks to companies like Zynga who build games specifically for the Facebook platform, giving them a captive audience of enthusiasts.

"For a company like Zynga, Facebook is absolutely the most efficient advertising platform in the world," business director Dan Rose said. "Games tend to be a leading indicator," he said. "As more and more categories become social, certainly that's an opportunity for us from an advertising perspective.

"We're in the middle of a transformation. We're moving from the information web to the social web. We're moving from the wisdom of crowds to the wisdom of friends," he said.

Mr Rose cited music and video as other advertising categories that could make money.