“A new version of the SoBig computer worm, expected in September, could not just overwhelm networks with infected mail but also lead to a massive increase in spam, according to some experts.

Many believe the SoBig.F computer worm, which infected many thousands of computers earlier in August, was designed to turn machines into ‘zombies’ capable of sending out a flood of spam. Data collected by the UK email-filtering company Message Labs shows that almost half of all computers sending spam have been infected with a computer virus. SoBig.F is programmed to stop working on 10 September and anti-virus companies say another variant may soon follow.” New Scientist