In an age of viruses, fraud and identity theft, who should be responsible for policing the Internet?

Governments, private security companies and law enforcement agencies all play a part in tackling cyber-crime.

But author and academic Jonathan Zittrain argues that we should be wary of “locking down” the Internet with increasing amounts of centralised rules and sealed gadgets that can’t be tinkered with.

In a new book published by Penguin and Yale University Press, he says part of the answer lies in greater freedom and trust, rather than more rules or technological solutions.

We don’t have police on every street corner in the real world, so why have that online, he asks?

People should be encouraged to see themselves as “netizens” — active participants in the online world, rather than passive consumers of Internet content.

They could share the load of policing the net, reporting threats and working together to combat the risks.

He says Wikipedia has shown that online collaboration can work.

“The challenge to the technologists is to build technologies to let people of good faith help without having to devote their lives to it,” he says.

Supporters say it’s just common sense, while at least one critic has described the approach as “utopian”. Who do you think should shoulder the burden of Internet security?

First there was “phishing” - where criminals try to steal people’s personal details using dodgy emails that look like they’re from the bank.

Then there was “spear phishing” - more sophisticated, targeted attempts to defraud specific organisations or their customers.

Now online fraudsters are trying to land even bigger catches by harpooning company bosses and their senior managers.

This latest and most audacious technique is called “whaling”

Fraudsters attempt to lure executives to reveal sensitive details about their business or click on a link in an email that will secretly download malicious software onto their computer.

Criminals could then attempt to defraud the company using the information they quietly gather.

Guy Bunker of Symantec, the Internet security company, says: “Whaling is basically going after the big fish in the sea. It’s targeting people at the top of the organisation.”

“There have been attacks in the States where a whole bunch of CEOs get sent a very official looking email that say you’ve been subpoenaed in court. If you click on this link you’ll get the citation.”

The link was the bait and the boss has exposed his corporation to fraud.

The extent of that problem was laid bare at Infosecurity Europe, an annual computer security conference held in west London.

A government-sponsored survey carried out by PricewaterhouseCoopers said online fraud costs the British economy alone about 6 billion pounds a year.

And with more business carried out online, the problem shows no signs of going away.

Lord Erroll, a technology expert in the House of Lords, told the conference: “The world isn’t going to change with a new generation coming through. It will have gullible and greedy people in it as well.

“So there will be people who do things wrong and are stupid and get conned. Technology alone isn’t going to protect people.”

Ofcom says millions of children who use social networking sites are exposing themselves to potential danger by leaving their privacy settings on “open,” thereby allowing all and sundry to peruse their personal details.

Its figures show a no less than a quarter of all children aged 8 to 11 in Britain, are registered with a social networking site.

It is the latest in a long series of warnings about Internet danger to children — which may suggest that either the children or their parents do not seem to care too much.

Do you think users are being too blasé, or are the dangers being exaggerated? Have you ever had any personal experience of the dangers Ofcom and others warn us about?