Trackers Using Facebook's Login Feature to Gain Users' Data

Third-party tracking code, used across the Internet to track user behaviors on websites, optimize ads and other purposes, has been grabbing Facebook user information on websites that support logging in through the social media platform, Princeton researchers report. When users log in to websites using Facebook’s Login feature, trackers can grab Facebook user IDs and in some cases other information such as email address or gender, potentially without the knowledge of the operators of the websites where the trackers are installed, according to the researchers.