because those advertisers do know you that well.
Search companies like Google feed your queries to advertisers, who use them to show you ads related to your interests—and that is just on Google’s site.
When you click search result links, the sites you visit can access your search terms and your I.P. address, which can determine the location of the computer you are using. That means those third-party sites also know what you searched for and who you are or at least where your computer lives.
In addition, your search history can create something called a filter bubble. As you build up a history of clicks and queries, Google will start delivering search results tailored to what it thinks you want to see. As a result, your results start to reinforce your worldview or even start to be less accurate, as you see only sites like those you have clicked on before.
For me, the right combination of privacy and search convenience came from making DuckDuckGo the default search engine in my browser. I like its instant search results, which appear above the rest of the results, and it’s fast and accurate. Ads are clearly marked and often relevant.
While Google does give users some control over their web and search activities and ad tracking, it will always be in that company’s best interest to share your information to serve you better ads and to collect as much as they can. That is not necessarily in your best interest.
Privacy matters for many reasons, both tangible and not, and it’s wise to exercise control when you can.