In recent months, several botnets have been taken down through a variety of legal and technical methods. However, according to Google survey, spam levels have remained stable despite these supposed disruptions.
“This suggests that there's no shortage of botnets out there for spammers to use,” Postini researchers say. “If one botnet goes offline, spammers simply buy, rent, or deploy another, making it difficult for the anti-spam community to make significant inroads in the fight against spam with individual botnet takedowns.”
While spam numbers did fall slightly for the forth quarter of 2009, the levels remained “relatively steady” for quarter one of 2010.