Facebook hits 500-million-member mark

Time to drop the blue and white confetti.

Facebook, the social networking site launched by a Harvard University student in 2004, officially hit the 500-million-user mark earlier this morning – more evidence of just how central Facebook has become to today's Web world. Only a few months ago, of course, Facebook was touting the arrival of its 400 millionth member, meaning the site has apparently grown by 25 percent since February.

"This is an important milestone for all of you who have helped spread Facebook around the world," Facebook founder Mark Zuckerberg said in a blog post this afternoon. "Now a lot more people have the opportunity to stay connected with the people they care about." Zuckerberg went on to include a few recent Facebook success stories, including the unlikely tale of Danish Prime Minister Anders Fogh Rasmussen, who used Facebook to find jogging partners.

It's been a tumultuous year for Facebook. The site has been condemnend by irate critics and repeatedly slammed for ignoring the privacy concerns of its users. Most recently, Facebook was taken to task by a coalition of ten privacy groups, including the ACLU of Northern California and the Electronic Frontier Foundation. The coalition asked Facebook to close several outstanding security loopholes and prohibit third-party app developers from revealing user data.

In June, The New York Daily News reported that Facebook had raked in $800 million in revenue in 2009, a figure that well exceeded previous estimates. An anonymous source at Facebook also told the Daily News staff that Facebook was finally earning "a solid net profit, in the tens of millions of dollars last year." Meanwhile, for at least one day this spring, Facebook beat out Google – the reigning traffic champion – to become the most-clicked site in the US.