Auditing the Impact of Cross-Site Web Tracking on YouTube Political and Misinformation Recommendations

TL;DR

This paper investigates how cross-site web tracking influences YouTube's recommendations related to politics and misinformation, revealing the impact of off-platform browsing activity and evaluating privacy tools' effectiveness.

Contribution

It introduces a sock-puppet experimental framework to measure the effect of cross-site tracking on YouTube recommendations and assesses privacy browsers' protective capabilities.

Findings

Cross-site tracking significantly influences YouTube's political and misinformation recommendations.

Privacy-focused browsers can mitigate, but not fully eliminate, tracking-driven recommendation biases.

Off-platform browsing history impacts YouTube content suggestions beyond on-platform watch history.

Abstract

YouTube has today become the primary news source for many users, which raises concerns about the role its recommendation algorithm can play in the spread of misinformation and political polarization. Prior work in this area has mainly analyzed how recommendations evolve based on users' watch history within the platform. Nevertheless, recommendations can also depend on off-platform browsing activity that Google collects via trackers on news websites, a factor that has not been considered so far. To fill this gap, we propose a sock-puppet-based experimental framework that automatically interacts with news media articles and then collects YouTube recommendations to measure how cross-site tracking affects the political and misinformation content users see. Moreover, by running our audits in both tracking-permissive and tracking-restrictive browser environments, we assess whether common privacy-focused browsers can protect users from tracking-driven political and misinformation bubbles on YouTube.