As far as my understanding goes and through comments here[1] Google's other toolbar(s) are also capable of sending clickstream data. The only thing new might be

As far as my understanding goes and through comments here[1] Google's other toolbar(s) are also capable of sending clickstream data. The only thing new might be the introduction of UserID as now the +1 Extension has user logged in, but I am not sure how that puts additional risk/privacy concerns. Secondly, a lot of addons/extensions are actually asking for permissions to all visited pages - it should not be hard to figure out who the current logged in person is, if you do have malicious intent (Scraping opened FB/Gmail web pages) . There is inherent privacy risk in using extensions with a lot of permissions! [1] http://www.quora.com/Google-Bing-Controversy-February-2011/Does-Google-Toolbar-send-clickstream-data-like-Bing-Toolbar http://www.quora.com/Google-Bing-Controversy-February-2011/D...