Engineers sound off on Google’s Privacy Sandbox at IAB Tech Lab cookies event

Marketers are on a long road to compensate for the void that will be left once Google deprecates all third-party cookies in Chrome by the end of 2024. Google’s solution — its Privacy Sandbox — may only complicate the matter.

Frustrations with Google’s Privacy Sandbox bubbled to the surface last week at the Interactive Advertising Bureau (IAB) Tech Lab’s As the Cookie Crumbles event in Manhattan, coinciding with the watchdog’s 10th anniversary.

At the event, a panel full of engineers working for major ad players (Index Exchange, Dstillery and Microsoft Ads — all members of IAB Tech Lab’s task force that first analyzed Privacy Sandbox in February) shared their critical feedback. They weren’t shy about taking jabs at the technology, even as Amit Varia, director of product management at Google, joined them on the panel, reassuring them that the product is in its early stages and can be improved with all parties in mind.

On a panel called “Be Nice When You Play in the Sandbox?” Joshua Prismon, chief architect at supply-side platform Index Exchange, described a “number of challenges” around the Privacy Sandbox, including gaps in documentation, not enough testing volume when it comes to data, and the need for ongoing investment in terms of education and engineering hours. But primarily, a major issue is essentially reconstructing what Google calls “building blocks.”

He likens the process of analyzing the technology to that of a deconstructed McDonald’s Big Mac. “Part of the thing we’ve had to do is try to pull those ingredients and make it a meal,” he said. “We’ve tried to do that with the gap analysis, but at the end, we’re still trying to figure out why there’s lettuce in the shake. It doesn’t quite work out there.”

Isaac Foster, principal engineer at Microsoft Ads, described the Privacy Sandbox as almost a new computing model. One has to think differently about how to write code to support it, he said, adding that he sees fear in the eyes of his team members when the project comes up. “It’s been a challenge aligning,” said Foster. “We’re trying to align browser people with ad tech people.”

Of course, even outside of the complex technical elements of the Privacy Sandbox, there are concerns around how this new paradigm will impact the open web.

“When we look at something like the Privacy Sandbox, we’re not looking at something that is communally owned, we’re looking at something that’s Chrome-specific, and Chrome is obviously very important to all of us, Google’s support for ad tech is clearly very important to all of us, but what we are not clear about, is, what is the governance going to be going forward, and how are we going to manage change and evolution within the Privacy Sandbox?” asked Brian May, principal engineer at Dstillery.

“What is the potential for that to impact our business models? How will we get enough forewarning so that if there’s a decision to change some aspect of the APIs that we’re dependent on, that we’re going to be able to respond to that in a timely manner and not, like with cookies, predicate our business model on something that is unilaterally removed?”

Foster said he sees hope in the long term for a more privacy-focused future but also worries about how this will impact the industry in the next year or two. “In the short term, we may end up creating a lot of incentives and changing the market in such a way that there’s a lot of disruption that can’t be recovered, from an open-web perspective.”

The event came amid mounting tension among Google, ad exchanges, brands and the industry’s governing bodies around the Privacy Sandbox.
In February, the IAB Tech Lab first spoke out about the pitfalls of Privacy Sandbox after its task force found that only a few of the 44 basic digital advertising use cases it analyzed could be supported through the initiative. “What we’re saying is that many of the building blocks in the Privacy Sandbox aren’t effective or robust enough, and in some cases they’re simply dysfunctional,” Tech Lab CEO Tony Katsur told AdExchanger at the time.

A week later, Google retorted that Privacy Sandbox is not a complete replacement for cookies and that past digital advertising tactics will have to be stopped anyway to build a privacy-conscious safe internet.

On last week’s panel, Google’s Varia shared a similar view. 

“It’s not intended to be a drop-in replacement for any specific advertising solution; it’s really just that building block for you to go build what is necessary for your customers,” explained Varia. “We are very eager to engage with the ecosystem. There’s a lot that’s possible. It’s important to keep an open mind on how it can be done.”

As a final takeaway, Prismon made a plea for any “expertise on the ad tech side” to help the industry navigate the complexities of the Privacy Sandbox, asking for businesses to “free up their time.”