The Google Dashboard is the one stop center that allows you to view and control data associated with the different products you use with your Google Account.

As per Google Official Blog:

In an effort to provide you with greater transparency and control over their own data, we’ve built the Google Dashboard. Designed to be simple and useful, the Dashboard summarizes data for each product that you use (when signed in to your account) and provides you direct links to control your personal settings. Today, the Dashboard covers more than 20 products and services, including Gmail, Calendar, Docs, Web History, Orkut, YouTube, Picasa, Talk, Reader, Alerts, Latitude and many more. The scale and level of detail of the Dashboard is unprecedented, and we’re delighted to be the first Internet company to offer this — and we hope it will become the standard. Watch this quick video to learn more and then try it out for yourself at www.google.com/dashboard.

Now you can find out how much Google actually know about you.