Some people love it. Others say it damages social relationships. Teenagers spend half their lives on it writes Mark Andrews.

Today the founder of Facebook announced the social networking site has more than 500 million members. That is nearly eight per cent of the world’s population using the the site to keep in touch with their friends, family and work colleagues.

The “important milestone” comes only months after Facebook announced that 400 million users were active on the site.

The feat is all the more remarkable for the fact that the site was founded just six years ago, in the college room of a young student called Mark Mark Zuckerberg who wanted to keep in touch with his friends.

The website, which was originally created for college students to keep in contact with one another, was launched in 2004 by Mr Zuckerberg and co-founders Dustin Moskovitz, Chris Hughes and Eduardo Saverin in their dorm room at Harvard University.

Now it is one of the busiest websites in the world – people spend 500 billion minutes a month trawling through the site. The company – which is based in Palo Alto, California – now employs more than 1,400 people around the world.

“This is an important milestone for all of you who have helped spread Facebook around the world,” Zuckerberg said today. “Now a lot more people have the opportunity to stay connected with the people they care about.”

He predicts the company is likely to reach the billion-user mark, but others are sceptical about this claim, suggesting the current figure could well be a peak.

The average Facebook member has more than 130 friends and creates 70 pieces of content each month.

In the last five months it has gained more than 100 million unique users – those who returns to the site more than once in a month.

Privacy

The large number of users, and the information they post about themselves online, has made the website vulnerable to criticism over its privacy settings.

Online security experts, internet users and the European Commission lambasted the company over alterations of the privacy settings which made it more difficult for users to keep their personal information private.

Recently Facebook, which says privacy is a “top priority”, launched a new “simplified” setting to enable users to easily safeguard their data.

The rapid growth of users has come as bad news to other social networking sites such as Bebo.

The website, which was launched in 2005, was recently saved from the axe after AOL sold it to Criterion Capital.

It has 4.4 millions members in the UK who were responsible for generating well over half of the social networking site’s 1.9 billion page impressions a month.

Online rumours are speculating that web giant Google is planning to take a step into the social networking market and could launch its own site in the near future.

But some commentators believe the site could be a victim of its own success, and the fact that it now has so many members could actually be its downfall.

“The thing that made Facebook attractive at first was that the people who went there at the beginning found a lot of their friends on it, because it was limited to their colleges or schools,” says Aleks Krotoski, says social psychology expert Aleks Krotoski.

“It was a strong network, because it was closed, and so people thought it was a safe environment.”

It’s the overlap of social groups: in the real world we can be very careful about who sees what aspect of our personality.”

There’s our work, our friends, our family, at home, on holiday. But on Facebook, the people you work with who are your ‘friends’ see everything.”