Preprint 2024 Paper 1
Title: Unearthing Privacy-Enhancing Ad Technologies (PEAT): The Adoption of Google’s Privacy Sandbox
Authors: Garrett A. Johnson (Boston University)
Abstract/Summary: As privacy regulations reshape the digital advertising landscape, the industry is turning to privacy-enhancing ad technologies (PEATs) to reconcile relevant advertising with consumer privacy. Google’s “Privacy Sandbox” is the leading initiative, offering tools designed to replace third-party cookies. These technologies, however, are already under regulatory scrutiny for their impact on market competition. We provide the first large-scale longitudinal evidence on Sandbox adoption, tracking almost 60,000 commercial websites from 2023 to mid-2025 with specialized detection methods. Adoption varied across technologies: the lightweight Topics API appeared on over 40% of sites, while the more complex Protected Audience API peaked at 23% on the advertiser side and 18% on the publisher side. Uptake accelerated through early 2024 but declined somewhat after Google paused—and later abandoned—cookie deprecation. Vendor adoption remains sparse, particularly for Protected Audience API, resulting in highly concentrated markets where Google retains a leading position. This persistent market power underscores the tension between improving privacy and ensuring competition in digital advertising. Our results, updated monthly on a public dashboard, provide timely, independent evidence for policymakers, practitioners, and researchers evaluating the role of PEATs in the future of marketing.