alphadogg writes "Despite security researchers' efforts to cut spam down to size, it just keeps growing back. The volume of unsolicited email in the first quarter was around 6 percent higher than a year earlier, according to Google's e-mail filtering division Postini. Security researchers have won a few significant battles against the spammers in the last year, first against those hosting the spammers' control systems, and later against the control systems themselves, but they will have to change tactics again if they want to win the war. In the first half of last year, security researchers concentrated their efforts on identifying the ISPs or hosting companies that allowed command-and-control servers to operate, and shutting these botnet purveyors down. The success of that tactic was short-lived, however."