Third-party tracking cookies are going away for 1% of Chrome internet traffic at the beginning of next year to start testing the post-cookie ad systems in conditions closer to the real-world ones publishers and brands will face once the trackers go away completely.

Google’s Privacy Sandbox team, the group working on the new ad tech that will dramatically alter internet ads and privacy online, laid out the latest timeline for cookie deprecation today. Cookies, of course, are the online trackers that are being phased out on Chrome, after Apple and other web browsers ditched them in recent years. Without cookies, websites and ad tech providers are turning to alternative methods to target and measure ad campaigns.

Google Chrome is working on an “identifier-less” ad tech ecosystem, which will share anonymous and aggregated data sets about web users to keep running programmatic ads online. Website publishers and their ad tech partners have been testing some of the systems being developed in Google’s Privacy Sandbox, but the tests have limitations. With third-party cookies still available, it is tough to see exactly what ad performance and revenue look like without them. That is why Google is now set to turn off cookies on 1% of all Chrome traffic in the first quarter of 2024, before turning off 100% of the cookies in the second half of the year.

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“We plan to deprecate third-party cookies for 1% of Chrome users, which is what is necessary to support developers in conducting real-world experiments,” said Victor Wong, senior director for product on Google’s Privacy Sandbox team, “to assess the readiness and effectiveness of products without third-party cookies.”

Cookieless timing

Google has been giving periodic updates to its Privacy Sandbox timeline and has even postponed the deprecation of cookies. What Google and online publishers are testing is a complete overhaul of how ads get targeted online and how marketers measure those ads. Instead of cookies, or other identifiers that rely on personal information, Google is developing APIs that websites plug into to access anonymous and aggregated data sets about web users.

Google, for instance, built a Topics API, which only tracks a limited, anonymous sampling of interests collected about a consumer, not an entire online history. Google also has what it calls a “protected audience API,” which enables cross-site advertising—retargeting consumers without disclosing personal data about them. The systems are being built to address ongoing privacy concerns in online advertising, but they also raise concerns for ad tech companies and competition. Google has had to build its new ad platform in ways that won’t hobble rivals that also sell internet ads, but they could be unduly affected by Google restricting data.

Publishers also want to protect their data and customers by not broadcasting the personal information of their web visitors, Wong said. The new protected audience API was designed to do that, Wong said, while still allowing publishers to participate in retargeted advertising.

“Under the new design of the APIs, publishers can make inventory available without worrying that their audience can be stolen,” Wong said.

There are concerns that ad revenue could suffer, hitting the online publishing industry once cookies are gone. Google has tried to show that it can maintain the value of ads and has released some research about the Privacy Sandbox tests. Last month, Google announced ads served without cookies were about 90% as relevant as ads with cookies, and that advertising spend under the new system declined between 2% and 7%.

Google released the new details of its timeline today so publishers and marketers can prepare for more robust tests. In the third quarter of this year, which starts in July, publishers will be able to fully turn on APIs that are related to ad relevancy and measurement, Wong said. Then, in the fourth quarter of 2023,  publishers will be able to individually simulate cookieless traffic, and compare the ad experience to traffic that still relies on cookies.

The test that starts in the beginning of 2024, when turns cookies off for 1% of Chrome users for all publishers, is more of a “universal” test, Wong said.

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