News

Microsoft Testing API To Enable Ads in Edge Without Third-Party Tracking

• By Kurt Mackie
• 03/05/2024

The Microsoft Edge Team on Tuesday explained their work on an Ad Selection API to address the impending disuse of third-party cookies in browsers.

The idea behind the Ad Selection API is to still preserve ad-supported content, while not permitting cross-site tracking, typically done via third-party cookies. The idea behind cookies is to preserve state in a browser session, which can be useful for some browser tasks, such as sharing profile information across sites. However, present-day uses go beyond such functionality and track user behaviors across sites, which is known as using "tracking cookies."

Cookie Tracking Deprecation Efforts
Microsoft appears to be way behind even Google in efforts to do away with third-party cookie tracking. Mozilla and Apple have led efforts and are deprecating third-party cookies this year. They were later joined by Google, per this 2023 Mozilla developer article. These browser makers are testing the effects of disabling third-party cookies gradually. They started the experiment by blocking third-party cookies with 1 percent of users in Q1 2024, for instance.

Mozilla already uses an antitracking policy in Firefox that blocks "third-party cookies from known trackers by default," according to The Mozilla developer article. Apple has a similar tracking prevention policy in Safari. The Brave browser "blocks tracking cookies by default." Microsoft described having a tracking protection feature in the Microsoft Edge browser back in 2019, based on "Disconnect's tracking protection lists." Microsoft also uses an "engagement score" to not block cookies on sites where the user is deemed to have an "established relationship."  

Microsoft's Tuesday announcement explained that it is advocating the use of the Ad Selection API as it "enables advertisers and publishers to show relevant ads to users -- all without relying on third-party cookies or other cross-site tracking identifiers."

The Ad Selection API is compatible with Google's Protected Audiences API but it "attempts to strike what we believe is a more stable long-term balance with content quality and industry innovation," according to the Web Incubator Community Group page description of the Ad Selection API.

The Ad Selection API differs from the Protected Audiences API by adding "differential privacy and k-anonymity output gates." It also avoids "shared services and failure points." Lastly, the Ad Selection API is said to make "operational excellence" the responsibility of ad tech.

Microsoft Edge Third-Party Cookie Deprecation
Microsoft 's Edge browser "will start experimenting with deprecating third-party cookies in the coming months, targeting less than 1% of non-managed device users, and continue throughout 2024," per Microsoft's Tuesday announcement. The testing won't be implemented across managed devices.

Microsoft Edge will block third-party cookies by default at some point, the announcement indicated, although the timing wasn't described.

Meanwhile, Microsoft wants its "commercial customers" to test their "public and internal sites" regarding the effects of third-party cookie removal. In the second half of 2024, Microsoft is planning to " invite testing and adoption of the Ad Selection API by the industry."