: Many profile "trackers" collect your device info and app activity, often sharing it with third parties for advertising or more nefarious purposes. Legitimate Ways to Interact with Private Profiles
Apps claiming to offer these features are often categorized by security researchers as: facebook private profile viewer by istaunch portable
Review and remove recently used third-party apps that have access to your Facebook data. Facebook·2600 - The Hacker Quarterly : Many profile "trackers" collect your device info