Study Finds Over 99% of U.S. Internet Users Encounter Ad Trackers, with Half Exposed to Advanced Surveillance Techniques

Global: Study Finds Over 99% of U.S. Internet Users Encounter Ad Trackers, with Half Exposed to Advanced Surveillance Techniques

A study posted on arXiv on Dec. 30, 2025, authored by Lucas Shen and Gaurav Sood, analyzes anonymized browsing data from a large, representative sample of American internet users to quantify the prevalence of online tracking and more invasive surveillance techniques.

The analysis shows that more than 99% of the participants encountered at least one ad tracker or third‑party cookie during the observation period.

Advanced Tracking Methods

While traditional tracking is nearly universal, the researchers also examined techniques such as session recording, keylogging, and canvas fingerprinting. Over half of the users visited a site employing at least one of these methods within the first 48 hours of the tracking window.

Dominance of Major Trackers

Linking trackers to their parent organizations revealed that a single entity—most often Google—can monitor over 50% of the web activity for more than half of the users.

Demographic Variations

Demographic differences in exposure were modest overall, yet disparities by age and race persisted even after accounting for browsing volume, indicating that the content of browsing, not just its quantity, influences surveillance risk.

The findings underscore that routine browsing habits contribute substantially to surveillance exposure, raising privacy considerations for policymakers, regulators, and technology providers.

Methodologically, the study combined passively observed, anonymized browsing logs with domain‑level tracking data from the Blacklight platform, enabling attribution of trackers to corporate owners while preserving user anonymity.

This report is based on information from arXiv, licensed under Academic Preprint / Open Access. Based on the abstract of the research paper. Full text available via arXiv.