DoubleClick's Legacy: How Google Tracks You Across Nearly Every Website
Google's ad network runs cross-site tracking at unprecedented scale, and its proposed Privacy Sandbox replacement raises new concerns
When Google acquired DoubleClick in 2007 for $3.1 billion, privacy advocates warned that combining the world's largest search engine with the web's most pervasive advertising network would create unprecedented surveillance capabilities. Those warnings have proven prescient. Today, Google's advertising and tracking infrastructure — the direct descendant of DoubleClick — operates on an estimated 85 percent of websites, giving Google visibility into the browsing behavior of virtually every internet user worldwide.
The mechanics of cross-site tracking are straightforward. When you visit a website that uses Google Ads, Google Analytics, Google Tag Manager, or any component of Google's advertising ecosystem, your browser loads code from Google's servers. That code drops cookies and identifiers that follow you as you move across the web, building a comprehensive profile of your interests, habits, and behavior.
Key Takeaways
- Google's advertising infrastructure operates on approximately 85% of websites, enabling near-universal cross-site tracking
- The Privacy Sandbox was criticized as replacing one surveillance system with another that gives Google more control
- Google reversed its plan to deprecate third-party cookies, opting for a choice-based model that is unlikely to change user tracking outcomes
