This summer Google started actively trying to warn users away from dangerous places on the Internet. If you try to click on a link furnished by a Google search, you might get a screen that screams, "Warning--the site you are about to visit may harm your computer! You can learn more about malware and how to protect yourself at StopBadware.org." Eventually, a general warning will be replaced by detailed information on a given site's record of distributing code that aims to steal data, send spam, or generate pop-up ads. Such records are being compiled by StopBadware.org, a creation of researchers at Harvard Law School's Berkman Center for Internet and Society and the University of Oxford (with the backing of Google and other companies).

But given that a mini-industry in "search optimization" has sprung up as online companies try to get their sites ranked higher in Google search returns, how long before malware purveyors create an industry in malware-detection-avoidance optimization?