Google, Microsoft, and Meta Ignore Your Ad Tracking Opt-Outs, Audit Reveals

An independent audit has revealed that Google, Microsoft, and Meta continue to track users' browsing habits for ad-targeting purposes even after they opt out. The audit, conducted by the team behind the privacy-focused search engine webXray, examined traffic from California users visiting thousands of popular sites. They tested how companies handle opt-out requests submitted through the user's web browser, and unfortunately, more than half of the tested sites still used ad cookies after being told not to.

According to the report, Google's ad systems set an IDE tracking cookie in most cases, even when the browser submits a do-not-track preference. IDE tracking is a third-party advertising cookie that identifies a browser across sites, allowing Google to show targeted ads and measure ad performance.

Microsoft's advertising services allegedly behave similarly about half the time. And for Meta, it's even worse: The report says the tracking code publishers ...