'Dread' watches his PC boot up, then double-clicks his Internet service provider. He downloads a bulletin board for hackers and notes the day's latest tips. Minutes later, he's trying to rewrite the code for a university homepage, scribbling his name on the title page to prove his presence.

'Tips on how to break into websites are all over the Internet,' he says. 'There are bulletin boards for them, discussion groups, chat rooms and web magazines. Almost all of them say the information is to be used solely for self-protection - rubbish. It's all there to be used.'

Dread is 27, single, and working in the IT industry. His main targets are university sites. His motivation, he explains, is the sheer pleasure of knowing he can break into a site. Others have a more dangerous sense of mischief.

The Internet, with its emphasis on free speech, undoubtedly encourages subversive behaviour and also provides access to hacking methodology.

One revolutionary arm of the Internet is the bulletin board, where users swap gossip and expertise. Regularly updated information allows hackers to beat latest security measures.

One bulletin board tells how to retrieve emails from Hotmail accounts. The instructions are easily discovered and downloaded and easy for even novice hackers to understand. Last year, Hotmail's global service was disrupted for five hours when hackers broke in, and closed it down. The ease with which even elaborate servers are infiltrated is worrying to those trying to implement security. 'Online security must be a priority for companies wanting to trade on the Internet,' says Jason Wu, head of NetFront Communications, a California-based security firm that provides privacy for firms who do business on the Internet.

'Most of the hackers who have penetrated websites this week are amateurs,' he continues. 'None of them has resurfaced to boast about their exploits and successes, which is really how professionals make a reputation for themselves. These hackers don't seem to have any agenda either. They just want to shut down the Internet to other people.'

But these 'script kiddies' are increasingly chasing monetary gain. Last Christmas, CD Universe, a leading online music retailer, had its database of 300,000 accounts hacked into.

The hacker demanded $100,000 in ransom. When the company refused, the hacker threatened to post its customers' credit card numbers on the Internet. The bank details of 25,000 stolen accounts were made available for free.

Only the intervention of a service provider ensured the offending web page was removed from the Internet.