Global Web, Local Privacy? An International Review of Web Tracking

2026-04-18

AI Summary

This study addresses the tension between the territorial nature of privacy regulations and the global reach of online tracking, which constrains enforcement efficacy. It presents the first systematic comparison of tracking behaviors experienced by users from ten countries when accessing both global and domestic top-525 websites. Combining large-scale web measurements, cross-border access simulation, and tracker identification, the work evaluates the real-world impact of regulations such as the GDPR and CCPA. The findings reveal a “Brussels Effect,” with 28% of websites displaying cookie banners globally, as well as a “Brussels Shield” phenomenon. Notably, users who do not interact with cookie banners can substantially reduce tracking: on average, tracking connections decrease by 50.5% under EU access conditions, and German users avoid 48.5% of tracking simply by not clicking the banner.

Technology Category

• Application Domains: Transportation
• Machine Learning: Privacy
• Computer Vision: Motion & Tracking

Application Category

• Responsible Web: Consent frameworks and practices on the web
• Security and Privacy: Tracking, profiling, and countermeasures against them
• Web Mining and Content Analysis: Topic discovery and tracking

Abstract

Web tracking by ad networks, social networks, and other third parties is privacy-invasive. To protect users' privacy an increasing number of countries are adopting new privacy laws. However, a major reason why their application on the web is so challenging is that privacy laws are local while the web is global. To that end, we evaluate websites' tracker connections for ten countries for two sets of sites -- the global Common Top 525 and the Country-specific Top 525 sites. We find that Australia and the US (California) -- two of the three opt-out jurisdictions in our study -- have the highest level of web tracking while opt-in jurisdictions generally have lower levels. We also find that the Common Top 525 sites have 50.5\% fewer average tracker connections when accessed from EU countries compared to non-EU countries. Further, simply not interacting with cookie banners decreases trackers by 48.5\% for Germany, as measured for a sample of 36 Common Top 525 sites. These results suggest that the General Data Protection Regulation and the ePrivacy Directive have a tangible effect in reducing tracking. As 28\% of Common Top 525 sites show cookie banners in all ten countries, our results suggest a moderate Brussels effect. However, against the backdrop of global US ad tech practices, EU law primarily acts as a Brussels shield. Generally, we think that strong enforcement of privacy laws is key to increase user privacy on the web.

Problem

• web tracking
• privacy laws
• global web
• local regulation
• Brussels effect

Innovation

• web tracking
• privacy regulation
• GDPR
• Brussels effect
• cookie banners