Geeks earn $4600 a day selling penis pills online

An investigation by Russian security researcher Dmitry Samosseiko found most spam on email, search engines and social networking sites originates from well-organised Russian affiliate networks - known as "partnerka" - which pay people generous commissions for referring unwitting web users to their illegal products.

"Thousands of affiliates, each calling themselves a 'webmaster', work day and night to drive as much user traffic to their partners' stores as possible," Samosseiko, who is head of Sophos's Canada virus lab, wrote in a report.

"The stores sell fake watches, fake anti-virus software, fake pills and fake love - the webmasters get their commission, making thousands of dollars per day."

The affiliates refer people to the networks' products by setting up scores of bogus web pages and commanding "botnet" armies of infected computers to send spam. They use black hat search engine optimisation techniques - and even monitor search term trends - to ensure their pages appear towards the top of search results.

Software tools such as John22, A-Poster, Xrumer, ZennoPoster and DarkMail automate much of this process, including generating seemingly legitimate websites based on content from Wikipedia articles.

The affiliates are paid a commission for every product they sell or for every computer they infect with malware, depending on the type of scheme.