A Google search for "miserable failure" no longer returns the official biography of George W. Bush. Until yesterday, pranksters and activists were able to manipulate the Google search algorithm to associate a specific site with a chosen query by creating a sufficient number of Web links pointed at the target site, a practice known as "Google bombing."

Google has improved its analysis of the link structure of the Web to defuse such bombs. Using Google-bombed keywords now generally returns links pointing to news sites discussing the Google bomb rather than the target site.

In the past, the company dismissed Google bombing, but it changed its position to prevent the perception that its search results exhibit bias. "Over time, we've seen more people assume that they are Google's opinion, or that Google has hand-coded the results for these Google-bombed queries," explained Matt Cutts, head of Google's Web spam team, in a blog post.

Victims have included Jimmy Carter, Michael Moore, Tony Blair, Rick Santorum, and John Kerry. Public figures still have reason to worry. That's because Ask, Windows Live, and Yahoo are susceptible to the same kind of manipulation.