The service requires users to sign up--although Gmail users can just use their Gmail ID and password--to get Google started tracking their search histories. Once Google starts tracking, every query the user makes is recorded, and if he or she clicks on a results link, that result is also recorded. When a user enters a new query, the results page is accompanied by a "related history" link next to any search term when it appears. Users can also browse through their search history with a calendar, viewing when each search was made on what day. Users can also search the full text of any page which they reached from a Google results page.
The search history information is stored on Google's own servers, which raises questions about possible privacy concerns and use of the information for targeting advertisement. A Google spokesman said that the company does not plan to use information for any other purpose than to refine searches.
Users also have a number of privacy options that they can exercise themselves. The there is a button to "pause" the recording of queries for searches that users prefer not be saved, and searches already listed in the history can be deleted.