Funny story:

I went through the Google application process, which was long and arduous (but fun). I was waiting to hear a final decision by the Executive Committee. It had been over a week.

I was biding my time on-line. I came across a site where a group of parents wanted to know more about the child pornography problem, but were afraid to type "child pornography" into Google. I was like, they're all spineless, and typed it into the browser. I wanted to let them know that it would give them news articles and not actual child porn. I must admit that I did hesitate momentarily before hitting the return key.

So, it seems like there is an uneasy truce between search engines and the porn world. So long as people searching for porn get porn and people not searching for porn don't get porn, everyone is happy. That can be a very difficult line to define. There is a guy at Google, Matt Cutts, who had the unfortunate job of writing software to find that line.

So, I started talking about it with my friends on Facebook. It was like a contest to figure out who could get closest to the line without going over it. I found a good pair of queries that straddled the line pretty well. "pictures of beavers" showed me rodents, but "pictures of cocks" resulted in nary a chicken. I kept coming up with more and more perverted but innocent terms, which I won't mention here, to explore the dividing line.

At some point late in the evening, it occurred to me that one of the final things Google might do with my application was check my search history. Maybe there was some loophole where, if you were applying for a job there, it was ok to bypass the normal privacy guidelines. And if they did check my search history, they would find the most unsavory trail of disgusting queries you could imagine. And I got a little worried right then, I must admit.

Then I thought, well, if they really look and see what I am actually doing, exploring the line, they'll probably WANT to hire me. And right then I got the email offering me a job.

But to answer the question, no, Google does not look at your search history. It's encrypted and it would take a collusion of many people at Google to accomplish such a thing, and it would be known if such things happened.

It wouldn't help them, anyway. People research certain terms for reasons you can't possibly know, like the parents looking up "child porn", or reporters researching "domestic terrorism".