How Ad Tech Might Work in a Post-Cookie World

The back-and-forth of Google’s Chrome Privacy Sandbox proposals

Dovekey proposes an external 'key value server,' granting a degree of autonomy from Google.
Trent Joaquin/Google

Key Insight:

Despite the chaotic mess that has been 2020, Google announcing plans to withdraw support for cookies in Chrome is still ad tech’s biggest story.

The move reflects how laws such as the General Data Protection Regulation and the California Consumer Protection Act are curbing online user targeting.

Arguably, Apple’s intelligent tracking prevention (ITP) rollout, beginning in 2017, was a harbinger of how this societal shift was to force the hand of major platform providers in implementing cataclysmic changes that would impact the online ad industry. And given Chrome’s market share, the disruption caused by ITP will be magnified greatly come 2022.

The ‘cookie-pocalypse’ countdown

In January 2020, Google announced a two-year countdown before it will cease supporting third-party cookies, the common currency for the online ad industry, in its Chrome web browser, a move that prompted much existential dread.

Execs at IAB Tech Lab who had seen the writing on the wall since the debut of ITP quickly attempted to convene “Project Rearc” in an attempt to establish a new modus operandi for the $565 billion industry, a feat that would require an unprecedented degree of consensus, not to mention public education.  

Privacy Sandbox

Simultaneous to its 2022 announcement, Google’s Chrome browser team—an important distinction—announced Privacy Sandbox to replace pre-existing cross-site tracking technologies.

Instead of cookies, it proposed the ad industry use aggregated data based on anonymized identifiers, or APIs, to assess ad performance, like these:

  • Trust Tokens – An anonymous means to verify traffic is generated by a user, not a bot
  • Click Through Measurement – An alternative to cookies to help measure conversions
  • Federated Cohort Learning – Software to study the habits of similar user groups
  • Private Interest Groups, Including Noise (PIGIN) – A means for advertisers to track interest groups

The key element of the proposal was that all auction decisions would take place in the browser rather than in a third-party ad server.

Buy-side sources questioned how critical trading functions like frequency capping and brand safety would work in such an environment. Some feared this was a case of the dominant becoming more powerful.

Deliberations via W3C   

Adweek first reported on plans to kill third-party cookies in March 2019 when Google sources spoke of its wariness over antitrust concerns. These are coming to a head to the extent that it set up distinct working groups to deliberate the future.

Hence, Google has been at pains to make details of Privacy Sandbox available via open-source forums such as GitHub with the proposals also debated at web standards body W3C. Here, the practicalities of such proposals are open to peer review.

Privacy Sandbox’s PIGIN proposal was initially poorly received, and effectively, is now off the slate.

Google’s own advertising team, distinct from the Chrome browser team, subsequently proposed a set of standards named Turtledove, which aimed to reconcile privacy concerns over PIGIN.

Essentially, it proposed the software that would derive what “interest group” online audiences belong to, generated within the Chrome browser.

Advertisers bidding on a particular ad impression would be unable to combine that information with other datasets, meaning third parties, and publishers, wouldn’t be able to glean as much information on a website user as in the past.

Enter indie ad tech  

As the financial ravages of Covid-19 took hold, some hoped the crisis would lead to a stay of execution, but earlier this week, Google told AdExchanger that “2022 is going to happen.”

The ad-tech independents then entered the fray with Criteo offering its Sparrow proposal—an acronym for “Secure Private Advertising Remotely Run On Web Server.” Meanwhile, Prebid, a body popular with publishers, proposed the Publisher Auction Responsibility Retention Revision of Turtledove (Parrot).  

In summary, both proposals advocated the removal of control from the browser while attempting to make privacy provisions raised in the initial reaction to PIGIN.

“As such, we think Turtledove could be improved further by allowing the publisher to retain control of the auction,” reads the Parrot proposal.

Meanwhile, Criteo’s vp of product Charles-Henri Henault explained how Criteo’s Sparrow proposes the auction process is controlled by an independent “gatekeeper,” and that Google’s Turtledove proposals would hit scalability issues.

“This is especially the case when this [auction] is run on a device that is increasingly mobile; therefore, it has limited storage and bandwidth,” he said, explaining that Turtledove would also risk using a huge degree of consumers’ mobile data plans.  

Google’s ‘open’ mindset & Dovekey

Given its notoriety as a “walled garden,” there is a perception that Google’s preference is for unilateral decision-making, and that any such deliberations with W3C peers are mere public posturing.

However, sources tell Adweek the giant is purposely taking a collaborative approach with the Google Ads team’s subsequent Dovekey proposal—an apparent acknowledgement of the merits of Criteo’s proposals—airing on GitHub recently.   

While Dovekey may fall short of Criteo’s wishes (by keeping the auction in the browser), it does propose an external “key value server,” granting a degree of autonomy from Google. For some, this would address concerns around ad load and the potential for bias in the wider Google stack.

For Paul Bannister, chief strategy officer at CafeMedia, Dovekey is a sign that Google is willing to collaborate. Although, in light of recent developments in regard to antitrust developments, he also believes the timing of the move may be politically motivated (see below).

Bannister also points to potential developments later in the month as W3C members will continue to debate the Privacy Sandbox proposals mooted in recent months, including the potential to merge all three.

The trade body will also be holding TPAC [Technical Plenary and Advisory Committee] meetings this month, an annual event where it is expected the proposals will make a significant step forward.

“A lot will happen in October, so it’ll be interesting to see kind of where we end this month,” said Bannister, whose company is a W3C member.

Bannister said the proposals represent positive steps in addressing the ad industry’s cookie problem, but that they’re still relatively vague and don’t dive into the “nitty gritty details” of how they’re going to work, especially when it comes to solving for measurement and attribution—a must for marketers.

“It doesn’t matter if advertisers can target well. If they can’t measure, and they can optimize their campaigns, that’s huge. That’s a bigger issue than the auction itself, and that’s where people are beginning to focus more of their attention,” he added.

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