WhoTracks .Me: Shedding light on the opaque world of online tracking

TL;DR

This paper introduces a large-scale, privacy-preserving measurement method for online tracking using a browser extension, providing the most comprehensive real-world data on tracking behaviors over a year.

Contribution

It presents a novel browser extension-based measurement approach and deploys it to over 5 million users, enabling accurate, long-term tracking analysis across diverse environments.

Findings

Largest dataset of real-world tracking over 1.5 billion page loads

Tracking behaviors vary significantly across countries and ISPs

Provides transparency and insights into online tracking practices

Abstract

Online tracking has become of increasing concern in recent years, however our understanding of its extent to date has been limited to snapshots from web crawls. Previous at-tempts to measure the tracking ecosystem, have been done using instrumented measurement platforms, which are not able to accurately capture how people interact with the web. In this work we present a method for the measurement of tracking in the web through a browser extension, as well as a method for the aggregation and collection of this information which protects the privacy of participants. We deployed this extension to more than 5 million users, enabling measurement across multiple countries, ISPs and browser configurations, to give an accurate picture of real-world tracking. The result is the largest and longest measurement of online tracking to date based on real users, covering 1.5 billion page loads gathered over 12 months. The data, detailing tracking behaviour over a year, is made publicly available to help drive transparency around online tracking practices.