The number do-it-yourself business scams on the web will increase, as spammers piggyback on the worry over job losses caused by the economic downturn, says McAfee.

According to the security firm's Spam Report 2009, web users will see an increase in spammers abusing free web-hosting and blogging sites because they don't require the purchase of a domain name. Corporate blackmailing will also become a big threat during 2009, with more and more sensitive personal and corporate data being traded on the online black market.

In its report, McAfee also revealed that in 2008, the US presidential election was the most popular subject for spam, closely followed by junk emails advertising credit cards and offering and ways to improve credit ratings.

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The removal of US ISP McColo last year initially caused a 65 percent decrease in global spam and McAfee claims spam levels are still not back to normal. However, it predicts that in 2009 a number of hosting companies will be set-up worldwide and will target the spammers who had been using McColo. This will result in spam levels rising again.

Jeff Green, senior vice president, McAfee Avert Labs, said: "Spammers have become smarter, quicker and more professional with their attacks and are leveraging what's in the news more than ever to tailor their messaging. With more people out of work or self employed going into 2009, beware of communication offering low-cost degrees and do-it-yourself kits as well as any requests for financial information from what looks like your bank, school or investment firm".

See also: Analysis: what 2009 holds for spam email