“The data collected here goes far beyond merely exposing the sites that you visit and your search history. This data includes the full address of the page, the page title, the referer URL, a unique user identifier (UID), your OS version, your country code, browser name and its exact version number, whether you previously visited the page, and other information. Wladimir Palant, the creator of the AdBlock Plus ad-blocking extension, found that the Avast Online Security and AVG Online Security extensions were collecting much more data than they are intended to, including detailed user browsing history.
While these extensions certainly appear helpful, they were caught snooping on user’s browsing habits in October this year.