Google's latest project is called Web History, and it offers registered Google Account users a chance to peruse not just their account history with Google, but one's surfing history.
The data is available only when the user logs on with a Google account and password, the same account used for other Google services such as Gmail. 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 can be turned off and on as you like.
Google Web History replaces the earlier "Search History," which only allowed users to look at previous web search queries and results. The new tool allows users to browse pretty much anything they've surfed on the Internet–from sites visited to downloads to search results, and also displays usage trends, 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.
Photo by Google.