The concept of privacy on the Internet is naive at best. Fact is everybody tracks what you do online. Collusion for Chrome, however will show you exactly where your information goes when you're served a cookie.
Collusion is a simple extension for the Chrome browser and is currently available at the Chrome Web Store. According to the developer, disconnect.me,
Thousands of companies and organizations secretly collect your personal data when you use the web, creating a shadow web of connections between sites you go to and trackers you probably never heard of. Collusion for Chrome graphs the spread of your data from sites to trackers, in real time, to expose these hidden connections.
The extension sits quietly in your browser bar, monitoring those shadow connections and generating a graph like the one above. It represents roughly 15 minutes of my web surfing. The circled planets are ones I've actually visited, the halo-less ones I have not. Red circles indicate a known tracking site, grey ones are potential trackers, and blue ones are originating sites.
And, while you can't actually do much to actually stop the tracking, it's interesting to see how exactly your information just sort of, well, leaks as you move about the 'Net. [Chrome Web Store via Bianca Bosker