Google now intends to deliver customized search results even to those searching its site without having signed into a Google account.
Google keeps a history of your Web searches for up to 180 days, using what it says is an anonymous cookie in your browser to track your search queries and the results you most frequently click on. For several years it has allowed those with Google accounts to receive customized search results based on that history, but now even those without Google accounts will receive tailored results based on a history of their search activity, Google said in a blog post late Friday.
For example, Google described in a video how the query "SOX" might signal one type of search intent coming from baseball fans in Boston or Chicago, and another type of intent from an accountant closing the books on the quarter. Based on that particular person's search profile, Google can promote links to baseball scores or Sarbanes-Oxley details higher in search results than other links affiliated with those queries.
This, of course, is not just about search results. By building a profile of past searches, Google can also gain insights into what kinds of advertising you're most likely to favor, therefore placing more targeted (and expensive) ads alongside those search results
Privacy advocates will likely be put off by the fact that this is an opt-out rather than opt-in service. Beforehand, the customized search results were only available to those who were signed into a Google account, and although Google has always stored the search history of anyone who visits its site, it didn't change individual search results based on that history.
Google was careful to describe the procedure for opting out of personalized results, and emphasized that it doesn't know who specifically is attached to a given set of search queries. But in essence, even those who search Google without being signed in can now be used to help Google improve the targeting of its search results and its ads.