What is cross-site tracking?

Cross-site tracking is a method used by third-party entities (such as advertisers or analytics companies) to track a user’s browsing activity across different websites. For example, a user may browse shoes on an e-commerce site, and later see ads for those same shoes on a news site or social media platform. This tracking is often done using cookies, tracking pixels, or browser fingerprinting, which collect data on a user’s behavior without explicit consent.

A study found that 75% of user tracking occurs before users even have the chance to consent to cookies, raising privacy concerns. The goal of cross-site tracking is typically to build detailed user profiles for targeted advertising or analytics​. While effective for advertisers, it has led to growing calls for better transparency and privacy protections, with regulations like the General Data Protection Regulation (GDPR) addressing these concerns​.