The number of junk e-mails being sent to computer users around the world has risen more than 150 per cent in two months, as spammers fight back against efforts to shut them down.

In November, the level of spam junk emails fell dramatically after the plug was pulled on McColo Corp, an American Company accused of providing the gateway for much of the world’s junk emails.

But, in just a few weeks, the world’s biggest junk-email gangs appear to have regrouped, as spam emails have now almost recovered to the same levels as before McColo was shut down.

According to data compiled by Google, computer users can expect to receive more unsolicited emails this year than ever before.

Spam or junk e-mails are unsolicited messages sent in bulk. Most are advertisements for dubious products and fake get-rich-quick schemes.

Google’s analysis of spamming activity showed that the average PC user that was not protected with adequate anti-virus software would have received 45,000 spam messages in 2008, up from 36,000 from the previous years.

The research showed that on the day that saw the highest volume of spam last year, in April, some users were receiving an average of 100 emails every minute. The company said that all indicators suggest that the problem will continue to get worse as spam attacks become “more frequent and more ingenious”.

In November, McColo was taken offline in what was seen at the time as a significant victory against junk e-mailers. Security researchers accumulated evidence of alleged spamming activities at McColo, and persuaded its internet providers to get the web-hosting service to be taken down.

This apparently left junk email gangs scrambling to find new ways to send their messages, but as Spam surges once again, it looks as though junk-emailers are up-and-running once more.

It is notoriously difficult to target and shut down sources of spam. Investigators have to prove that company officials know that crimes are being committed through their servers. Web-hosting companies often argue that they do not monitor how customers use their services.

In the case of McColo, it appears that spam senders used the company’s servers to send commands to huge numbers of computers that they had in effect hijacked.

Spammers use networks of these compromised computers – known as “botnets” – to amass enough computing power to send millions of messages a day. The vast majority of owners of those machines do not know their computers are secretly being used for this purpose. But spammers need a way to communicate with these computers plus a web-hosting company willing to look the other way.

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