97% of email is spam, says Microsoft

Microsoft said that the financial downturn had even affected the content of spam messages. "In relative terms, the most dramatic change was seen in the category of stock-related spam, such as 'pump-and-dump' stock schemes," it said. "Mirroring the economic downturn experienced by much of the world in 2008, stock-related spam all but disappeared from [our] content filters [during the period], dropping to 0.6 percent of the total from 9.6 percent in [the previous year]."

Microsoft also said that spammers were sending out spoof email newsletters designed to mimic those of major news organisations such as CNN.

"The messages closely or exactly replicate the format used by the legitimate newsletters and typically feature a mix of real headlines and provocative-sounding false ones. Recipients who click the headline links are taken to Web pages that host spam advertisements or malware," it said.