"Google collects a good deal of information about your query. It records not only what you searched for (when you activate the advanced Toolbar features), but several other pieces of information as well, including the time of day, the type of browser you're running, the language your browser uses, and your IP address. Many times, after giving you a list of Web sites that match your search, Google will also record which sites you actually visited."
"Of course, the company collects all this information if you enter a query directly into Google.com without using the Toolbar. The problem with the Toolbar is that, if the app's advanced features are running, Google also keeps a record of every single site you visit—whether you're using the app to search the Web or not."
http://www.pcmag.com/article2/0,4149,904805,00.asp
Comcast ran into trouble doing something simliar keepin a record of everything you were doing.