A tidal wave of spam has been predicted this year as cyber criminals are increasingly targeting social networks such as Facebook.

The networking computer company Cisco estimated that worldwide spam volumes this year could rise by 30 to 40 per cent compared with 2009. Spammers already send out up to 100 million junk e-mails a day and, although the vast majority are never opened, enough people click on the links to make spam a multimillion-dollar industry.

Increasingly spammers seek to get people to click on links that download malicious software on to their computers to steal personal information including banking details and passwords.

These phishing scams have come mostly in the guise of e-mails from banks and financial institutions but recently spammers have hooked onto social networks. Users of Facebook, which has 350 million members worldwide, are much more likely to respond to messages that appear to come from friends.

In 2008 there were virtually no Facebook phishing messages. Today Facebook is the second most phished organization online and, if current trends continue, is on track to take the top spot in 2010, according to a report from a voluntary community of web defenders called Project Honey Pot.

The project was formed by web administrators as an alliance against online fraud and abuse in 2004. The group, which tracks and catalogues millions of spam messages a day, now numbers 40,000 members in 170 countries, making it the biggest effort of its kind on the net.

Matthew Prince, co-creator of Project Honey Pot and a professor of cyberlaw at the John Marshall Law School in Chicago, said: "Spammers are trying to establish trust and they see Facebook as the way in."

For more on this story, see The Times of London.