July 28, 2026 | SIGN UP
Ronan Shields
SENIOR REPORTER, AD TECH
Apple, Google, Meta and Mozilla are backing a W3C proposal that could place web browsers at the center of advertising measurement, reviving concerns raised by Google’s aborted Privacy Sandbox.
The Attribution API would measure conversions using aggregated data, privacy “noise,” and approved aggregation services rather than tracking individuals through third-party cookies. Supporters argue the system is being developed transparently through a multi-stakeholder standards process and would make attribution more auditable and privacy-conscious.
Critics, however, warn that browser providers would gain further control over what advertisers can measure and how. Former IAB measurement lead Angelina Eng told Digiday marketers need event-level data to build customized attribution models, rather than browser-constrained outputs. Meanwhile, Don Marti argued the proposal could also favor search, social, and app-store advertising — benefiting Apple, Google and Meta at publishers’ expense.
The central question is whether the W3C process can avoid Privacy Sandbox’s mistakes or institutionalize browser control across the entire web.
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