Facebook is expected to announce that it has reached 500 million users in the next couple of days, as the site continues to grow.

The news will give producers of the new film, "The Social Network", a big sigh of relief as the 500m count is one of the key lines in the marketing push.

"As we anticipated our 500-million milestone, and we wanted to find a different way to announce and celebrate it", Randi Zuckerberg told BoomTown, one of the blogs within the Wall Street Journal. "In the past, it’s been all about the numbers and milestones and we realized we had never taken the opportunity to celebrate users".

Those users will now be used in a campaign titled "Facebook stories" that shares its story with the world.

According to the site the stories, of which there will be around 200 to start with, will have two views - organised by geographical location and by theme, such as “finding love”, “coping with grief” and “natural disasters”.

The news comes shortly after the new trailer for Facebook is doing the rounds. The film, due out later this year, focuses around the site's creation and the battles that Mark Zuckerberg, its founder has gone through, and does not always paint him in a good light.