The problem with advancements in technology is the fact that the users’ privacy has a tendency to get in the way. Google launched Personalized Search on Tuesday and it now tracks where you go in order to give you better results in the future.
With the launch of Personalized Search, you can use that search history you’ve been building to get better results. You probably won’t notice much difference at first, but as your search history grows, your personalized results will gradually improve. –Google
Of course, in order for Google to track someone, they must have a Google account and be logged in. So if you don’t want Google following you, don’t log in any Google services before searching.