Google's latest project, Web History, offers registered Google Account users a chance to keep track of not just their account history, but their surfing history. The data is available only when the user logs on with a Google account and password, the same account used for all other Google services. In order to track web surfing information, the user must have the Google Toolbar installed in their web browser, and have PageRank enabled. The Web History feature, which can be turned off and on, replaces the earlier "Search History" feature, which only allowed users to look at previous web search queries and results. The new tool tracks everything, allowing users to re-visit sites, downloads, search results and so on, along with displaying usage trends and showing which sites were most visited at certain times of the day. There's even a history of which Google AdSense ads the user has clicked on.