With the way the RogueAv teams are using SEO to poison search results one of the isc.sans.org readers "Andy" submitted this idea in response to this article by Bojan.
http://isc.sans.edu/diary.html?storyid=9085

"If search engines were to ignore everything that is not "Visible" on a page they crawl, then a lot of this malware
would lose their stealth.
Drop all hidden, non formatted, and even white text on a white background.
It would improve search results."

Google may already be doing something like this as they are not getting hit as hard as some other search engines in the fakeav SEO poisoning attacks.
Thanks Andy.