Internet spam has earned a reputation as the cheapest form of advertising, in both class and the cost of producing it. Now we’re told that unsolicited email campaigns have very tiny response rates but still return a profit.

Computer scientists at the Berkeley and San Diego campuses of the University of California conducted their own spam experiments early in 2008 to see how effective that kind of advertising can be. They said they believe their experiment was "the first large-scale quantitative study of spam conversion."

Saying "the best way to measure spam is to be a spammer, "the researchers said they infiltrated part of a commercial spam operation for 26 days to send out nearly nearly a half billion unsolicited emails. They did this through a network of nearly 76,000 home computers that had been hijacked earlier by the commercial spammer.