Privacy Settings and Ad Perception: The Shift from Third-Party Cookies to the Privacy Sandbox

Paper Title

Privacy Settings and Ad Perception: The Shift from Third-Party Cookies to the Privacy Sandbox

Publication Info

• Topic area: User perceptions of privacy-preserving advertising technologies.
• Keywords: Privacy Sandbox, third-party cookies, online behavioral advertising, ad relevance, purchase intent, privacy perception, user study, Chrome browser, ad targeting, privacy-preserving technologies.

Background and Problem

• Problem / challenge: The deprecation of third-party cookies by major browsers has created a need for privacy-preserving alternatives that maintain ad effectiveness. Google's Privacy Sandbox aims to address this but its user perception and effectiveness remain underexplored.
• Significance: Understanding user perceptions of Privacy Sandbox is critical for its adoption and for balancing privacy with effective advertising in a post-cookie era.
• Motivation and related work: Prior research has focused on the technical and economic implications of Privacy Sandbox but has not adequately addressed user perspectives. This study fills that gap by evaluating ad relevance, purchase intent, and perceived privacy under Privacy Sandbox compared to third-party cookies and cookieless settings.

Solution

• Proposed approach: A user study comparing ad perceptions across three privacy configurations: Privacy Sandbox, third-party cookies (Status Quo), and cookieless settings.
• Novelty:
  1. First user study focused on Privacy Sandbox ad perception.
  2. Comparison of Privacy Sandbox with third-party and first-party cookie environments.
  3. Analysis of user privacy behaviors and their impact on ad perception.
• Procedure and key techniques:
  • Recruited 449 participants via Prolific.
  • Randomly assigned participants to one of three groups: Privacy Sandbox, Status Quo, or Cookieless.
  • Participants configured Chrome browser settings using feature flags and viewed ads on three publishers.
  • Collected survey responses on ad relevance, purchase intent, and perceived privacy violation.

Results

• Concrete findings:
  • Ads delivered via Privacy Sandbox were rated as less relevant (mean = 2.14) and less persuasive (mean = 2.24) compared to third-party cookies (relevance mean = 2.37, purchase intent mean = 2.46).
  • No significant improvement in perceived privacy protection with Privacy Sandbox (mean = 1.92) compared to third-party cookies (mean = 1.98).
  • Cookie acceptance positively influenced ad relevance (OR = 1.26) and purchase intent (OR = 1.25), while ad blockers negatively impacted both (OR = 0.52 and OR = 0.47, respectively).
• Advantage over baselines: Privacy Sandbox ads were perceived as more relevant than ads in the cookieless setting (mean = 1.99) but did not match the effectiveness of third-party cookies.
• Experiments / evaluation:
  • One-way ANOVA and logistic regression analyses were conducted on 1,050 valid survey responses.
  • Metrics included ad relevance, purchase intent, and perceived privacy violation.
  • Participants visited three publishers implementing Privacy Sandbox APIs.
• Limitations and future work:
  • Potential delays in ad configuration propagation.
  • Limited ability to verify whether ads were served exclusively through Privacy Sandbox APIs.
  • Small sample of publishers and short-term exposure to ads.
  • Future work should explore long-term user perceptions and include larger datasets.

Summary

This study evaluates user perceptions of Google's Privacy Sandbox compared to third-party cookies and cookieless settings. Findings reveal that Privacy Sandbox ads are perceived as less relevant and persuasive than third-party cookie–based ads, without improving users' sense of privacy. However, Privacy Sandbox offers incremental gains over purely contextual targeting. These results highlight the challenges of balancing privacy and ad effectiveness in a post-cookie world and suggest that Privacy Sandbox requires further refinement to meet user expectations and industry needs.