Audit Finds Google, Meta, Microsoft Ignore Opt-Outs

An independent audit released in March 2026 has uncovered that Google, Microsoft, and Meta continue to deploy tracking cookies on users' browsers even after they signal a desire to opt out of data collection for advertising purposes. The study, conducted by the privacy technology firm webXray, analyzed web traffic from California users across thousands of popular websites and found widespread noncompliance with state privacy laws.

The audit focused on the Global Privacy Control signal, a browser-based mechanism endorsed by California regulators to enforce users' opt-out requests under the California Consumer Privacy Act. This act grants consumers the right to decline the sale of their personal data. Researchers tested 242 advertising technology vendors and observed that 194 ignored these standard opt-out signals. Among the sites examined, 55 percent still set advertising cookies despite the privacy preference, while 78 percent of cookie consent banners failed to block trackers effectively. Notably, all 11 consent management platforms evaluated, including those certified by Google, permitted third-party tracking to proceed after opt-outs.

Google showed the highest failure rate at...