Several years after Google introduced Fledge to the world as one of a suite of cookie replacements, and nearly nine months after Google opened up the product to testing for the wider industry, the retargeting solution is gaining adherents, five sources told Adweek.

There’s some consensus that Fledge, an acronym for first locally executed decision over groups experiment, is a more viable cookie replacement than other solutions on the market because it mimics the existing processes of digital advertising while cutting out any identifier that could link people with their browsing history.

“[Fledge has] the scale and the ability to run classic models that advertisers and publishers have made a bunch of money with,” said Alex Cone, co-founder of ads privacy learning platform Coir.

Reflecting this increased momentum, nine new firms have begun testing Fledge since late September 2022, according to data from a web-sniffing tool collected by demand-side platform RTB House, itself an earlier tester. Fledge live auction testing has more than tripled since October, according to a Google spokesperson.

“Testing is critical to the success of the Privacy Sandbox, and we’re very encouraged by the increased interest in Fledge testing by the industry,” said Victor Wong, senior director of product management, Privacy Sandbox at Google. “Making programmatic advertising private-by-design is a significant step for consumers.”

The reaction to Fledge contrasts with the industry’s more negative reception to another Privacy Sandbox protocol, Topics. A working group of trade body W3C rejected Topics earlier this month, arguing it fails to protect users’ privacy. Since Topics was introduced last year, questions have mounted on whether it will really help publishers or marketers.

Despite the W3C criticism, a Google spokesperson told Adweek that it still expects the industry will use Topics, noting that only partners authorized by the publisher can access the data tied to Topics.

But any cookie replacement solution is only as valuable as how many industry players use it, especially as time runs out until Google’s 2024 cookie deprecation deadline. So far, Fledge may have the edge in popular support.

Targeting groups, not individuals

Fledge is a cookieless solution for advertisers seeking to retarget. Typically, visiting a shoe website, and leaving without making a purchase, means a user is likely to continue to see shoe ads since cookie technology identifies and follows them around the web.

With Fledge, visiting the shoe website places them in an interest group owned by the brand. When a consumer visits a publisher, the owners of all the interest groups they are part of can bid to serve them an ad (so long as they are invited). The entire auction happens on the user’s browser rather than the ad server.

The solution is more privacy safe than cookies because groups, not individuals, are the unit of targeting. Topics, meanwhile, are linked to individuals, albeit providing fewer signals about users than cookies.

[With Fledge] 100% of the audience is addressable. That’s massively powerful.

Alex Cone, co-founder of ads privacy learning platform Coir

Because the auction happens on the browser, users’ data does not end up getting held by various firms, said Lukasz Wlodarczyk, vp of programmatic ecosystem growth & innovation at RTBHouse.

“All parties have only partial visibility to what is happening, which is a guarantee for the user that no one will have full access to your browsing,” he said.

Because with Fledge the entire auction happens within the browser, versus occurring in various ad-tech platforms, match rates, or the percentage of data synced between the buy and the sell side, is higher for Fledge than third-party cookies, said Cone.

“Cookie matching might not match up. You might get an 80% [match rate] … Email you might match 30%,” Cone said, referring to email, first-party data-based cookie alternatives. “[With Fledge], 100% of the audience is addressable. That’s massively powerful.”

A common concern has been that cookie deprecation threatens to give walled gardens an even further advantage over the open web because companies like Meta and Amazon own so many web properties that they can offer marketers scale without having to track people across the web. Fledge gives publishers some ammunition against this reality, Cone said.

Still Fledgling

While more groups have been testing Fledge recently, it still accounts for only a tiny fraction of the bid requests that exchange OpenX runs in a day, said OpenX CTO Paul Ryan. That makes much of the discussion of Fledge more theoretical than results-based.

“While people are testing, there’s no significant revenue, there are no significant campaigns using the Fledge components,” Ryan said.

Case in point, after eight months of testing, Criteo said in a December 2022 blog post that it could not fully quantify Fledge’s impact on marketer effectiveness and publisher revenue, since key features like reporting capabilities and an A/B test framework had not yet been deployed.

Part of the holdup is that Fledge is very complex, more so than topics, sources said, and publishers’ resources are limited, said Don Marti, vp of ecosystem innovation at publisher network Café Media.

So far, Fledge’s biggest asset is that it maintains the status quo without sacrificing privacy too much, said a publisher ad-tech source who wasn’t authorized to speak to the press. But the status quo might be too low a bar.

“From the perspective of publishers, the status quo of ad tech hasn’t been particularly advantageous,” the source said. “It would probably make sense to blow it up a little bit.”