Facebook has 20 million users worldwide, is worth billions of dollars and, if internet sources are to be believed, was started by the CIA.

The social networking phenomenon started as a way of American college students to keep in touch. It is rapidly catching up with MySpace, and has left others like Bebo in its wake.

But there is a dark side to the success story that's been spreading across the blogosphere. A complex but riveting Big Brother-type conspiracy theory which links Facebook to the CIA and the US Department of Defence.

The CIA is, though, using a Facebook group to recruit staff for its very sexy sounding National Clandestine Service.

Checking out the job ads does require a Facebook login, so if you haven't joined the site - or are worried that CIA spooks will start following you home from work -check them out on the agency's own site.

The story starts once Facebook founder Mark Zuckerberg had launched, after the dorm room drama that's led to the current court case.

Facebook's first round of venture capital funding ($US500,000) came from former Paypal CEO Peter Thiel. Author of anti-multicultural tome 'The Diversity Myth', he is also on the board of radical conservative group VanguardPAC.

The second round of funding into Facebook ($US12.7 million) came from venture capital firm Accel Partners. Its manager James Breyer was formerly chairman of the National Venture Capital Association, and served on the board with Gilman Louie, CEO of In-Q-Tel, a venture capital firm established by the Central Intelligence Agency in 1999. One of the company's key areas of expertise are in "data mining technologies".

Breyer also served on the board of R&D firm BBN Technologies, which was one of those companies responsible for the rise of the internet.

Dr Anita Jones joined the firm, which included Gilman Louie. She had also served on the In-Q-Tel's board, and had been director of Defence Research and Engineering for the US Department of Defence.

She was also an adviser to the Secretary of Defence and overseeing the Defence Advanced Research Projects Agency (DARPA), which is responsible for high-tech, high-end development.

It was when a journalist lifted the lid on the DARPA's
Information Awareness Office that the public began to show concern at its information mining projects.

Wikipedia's IAO page says: "the IAO has the stated mission to gather as much information as possible about everyone, in a centralised location, for easy perusal by the United States government, including (though not limited to) internet activity, credit card purchase histories, airline ticket purchases, car rentals, medical records, educational transcripts, driver's licenses, utility bills, tax returns, and any other available data.".

Not surprisingly, the backlash from civil libertarians led to a Congressional investigation into DARPA's activity, the Information Awareness Office lost its funding.

Now the internet conspiracy theorists are citing Facebook as the IAO's new mask.

Parts of the IAO's technology round-up included 'human network analysis and behaviour model building engines', which Facebook's massive volume of neatly-targeted data gathering allows for.

Facebook's own Terms of use state: "by posting Member Content to any part of the Web site, you automatically grant, and you represent and warrant that you have the right to grant, to facebook an irrevocable, perpetual, non-exclusive, transferable, fully paid, worldwide license to use, copy, perform, display, reformat, translate, excerpt and distribute such information and content and to prepare derivative works of, or incorpoate into other works, such information and content, and to grant and authorise sublicenses of the foregoing.

And in its equally interesting privacy policy: "Facebook may also collect information about you from other sources, such as newspapers, blogs, instant messaging services, and other users of the Facebook service through the operation of the service (eg. photo tags) in order to provide you with more useful information and a more personalised experience. By using Facebook, you are consenting to have your personal data transferred to and processed in the United States."

Is the CIA really providing the impetus and the funding behind the monster growth of this year's biggest dot com success story? Maybe only the men with the nice suits and ear pieces can answer that.