New Web Tracking Technique is Bypassing Privacy Protections

Two years ago, several browsers that prioritize user privacy — including Safari, Firefox, and Brave — began to block third-party cookies for all users by default. Advertisers have responded by pioneering a new method for tracking users across the Web, known as user ID (or UID) smuggling, which does not require third-party cookies. But no one knew exactly how often this method was used to track people on the Internet.