There’ been a widely-reported story about a woman on Long Island whose house was visited by a bunch of government agents because of some online searches for pressure cookers and backpacks. Everyone, including the woman, assumed it was Google who tipped off the agents. Turns out, it was her husband’s former employer since at least some of the searches were done on a company computer.
While Google does routinely give up your search data to anyone who requests it, it’s also important to remember that your work computer, email, searches, etc. are also being monitored. If you think you have privacy, anywhere, you’re only fooling yourself.