I’ve touched on this previously.
You share your most intimate secrets with your search engine without even thinking: medical, financial and personal issues, along with all the day to day things that make you, well, you. All of that personal information should be private, but on Google it’s not. On Google, your searches are tracked, mined, and packaged up into a data profile for advertisers to follow you around the Internet through those intrusive and annoying ever-present banner ads, using Google’s massive ad networks, embedded across millions of sites and apps.