With the large amount of info being sent, Palant is concerned that the security companies could use this information to reconstruct a user's browsing history. This data includes the URL visited, page title, the referer, your OS version, a unique user identifier, your country code, whether you previously visited the page, and other information. While these extensions certainly appear useful, security researcher Wladimir Palant reported that these extensions are sending a large amount of tracking data about a user's browsing habits to.

SafePrice will display a small bar on ecommerce sites that alert users to better prices at other sites when shopping for various products. The Avast and AVG Online Security extension will alerts users to phishing, scam, and malicious sites when a user visits them. When Avast and AVG antivirus is installed, the software will also install their respective Firefox and Chrome extensions named Avast Online Security, AVG Online Security, Avast SafePrice, and AVG SafePrice. Mozilla has removed four extensions from Avast and AVG from the Firefox addon site over concerns that they were tracking a user's activity as they are browsed the web.