CNN.com: Criminal gangs using hijacked computers are behind a surge in unwanted e-mails peddling sex, drugs and stock tips.
The number of "spam" messages has tripled since June and now accounts for as many as nine out of 10 e-mails sent worldwide, according to U.S. email security company Postini.
As Christmas approaches, the daily trawl through in-boxes clogged with offers of fake Viagra, loans and sex aids is tipped to take even longer.
"E-mail systems are overloaded or melting down trying to keep up with all the spam," said Dan Druker, a vice president at Postini.
His company has detected 7 billion spam e-mails worldwide in November compared to 2.5 billion in June. Spam in Britain has risen by 50 percent in the last two months alone, according to Internet security company SurfControl.