Apparently spam is more than a nuisance on your eyes and index finger: It's also killing the environment. A report from McAfee released Wednesday finds that the amount of computing power required to send, process and filter junk mail is 33 billion kilowatt hours per year, or roughly the amount of electricity used in 2.4 million homes. To put the findings in perspective, McAfee said the energy saved when spambot hosting provider McColo was taken offline last year equated to the fuel savings of taking 2.2 million cars off the road for one day. — DK