Well duh! Black Hats have known this for a very long time. Ever since Chrome came out, in fact. When I first tried it, it suggested URLs I had visited while logged into Gmail on Firefox.....Chrome had a brand new history, how did it know what I did on the other browser? That was my first realization of what Chrome really was. I have never installed it since. But the news is it's going mainstream. It's all over Reddit and the media will pick this up soon. http://labs.detectify.com/post/133528218381/chrome-extensions-aka-total-absence-of-privacy TL;DR, Popular Google Chrome extensions are constantly tracking you per default, making it very difficult or impossible for you to opt-out. These extensions will receive your complete browsing history, all your cookies, your secret access-tokens used for authentication (i.e., Facebook Connect) and shared links from sites such as Dropbox and Google Drive. The third-party services in use are hiding their tracking by all means possible, combined with terrible privacy policies hidden inside the Chrome Web Store. The Detectify team has identified how they are doing it and what options you have to avoid being affected by it.