The before times
FLEDGE stands for “First Locally-Executed Decision over Groups Experiment,” which is exactly what it aims to do.
The FLEDGE API will enable interest-group-based advertising by tasking the browser with choosing which ads users see based on the sites they’ve previously visited. That’s the “groups experiment” part of the acronym.
In order to keep this data secure, FLEDGE proposes the browser conducts an on-device auction. That’s the “locally-executed decision” part of the acronym.
If the tech works as intended, it will support cross-site use cases without relying on cookies or other traditional tracking mechanisms.
Although retargeting is the biggie use case to keep in mind for FLEDGE, that definition is “a little too narrow,” said Michael Kleber, Google’s lead engineer for the Chrome Privacy Sandbox.
The best way to think about FLEDGE is as an alternative way to create custom audiences that aren’t tied to cookies, which goes beyond just retargeting. These audiences could be used for reengagement campaigns, frequency capping, to target in-market consumers or reach people based on their affinity, like “movie lovers,” “runners” or “cooking enthusiasts.”
So, how does FLEDGE work?
Sellers initiate the ad auction by calling the FLEDGE API. The browser’s job is to decide which ads to show based on the sites a person has visited and the type of people an advertiser wants to reach.
But how is FLEDGE different from the Topics API, which Google announced in January as the sandbox successor to FLoC? (FLoC, which stands for “federated learning of cohorts,” failed to make it out of the testing phase last year.)
Put simply, Topics is a less complex version of FLEDGE.
The Topics API creates audience segments on a weekly basis by inferring a small handful of topics users might be interested in based on the hostnames of the sites they visit. A topic might be “fitness,” “travel,” “entertainment,” “sports” or “health & beauty.”
Topics are stored for three weeks and updated weekly. In a nod to privacy protection, topic selection is done by the browser on a user’s device without the involvement of any external servers (including Google’s own servers).
But is FLEDGE viable?
Whether FLEDGE is a workable alternative to third-party cookies depends on how well it can replicate the functionality of said cookies and if it can move decisioning to the browser without overtaxing a user’s device.
For all their many faults, cookies track multiple ad performance drivers, said Nancy Marzouk, CEO and founder of identity data company MediaWallah.
Surfing behavior, for example, indicates a variety of interest-related data, including site content, purchase intent and demographic information, Marzouk said, and the recency of that data is also important.
But FLEDGE doesn’t take most of that into consideration, she said.
“FLEDGE only allows an advertiser, ad tech platform or publisher to define an interest and retarget that user based on previously expressed interest,” Marzouk said. “But it doesn’t take into account that the user might no longer be interested.”
Or the fact that users look at lots and lots (and lots) of different products as they browse the internet.
“Users might look at hundreds of web pages over the course of a few days, which could mean that hundreds of companies have asked their browser to store interest group information about them,” said CafeMedia’s Bannister. “That means for any opportunity on a publisher site, they’re eligible for potentially hundreds and hundreds of ad auctions.”
Clearly, there are some kinks to iron out during the ongoing origin trials.
But there’s another burning question: Does FLEDGE do what it says on the tin and protect user privacy?
One of the main reasons FLoC failed to fly and why it was replaced by the Topics API is because it wasn’t necessarily more privacy preserving than cookies. It was still possible to do cross-site tracking and fingerprinting using FLoC IDs.
But FLEDGE has baked in privacy fail-safes, said Łukasz Włodarczyk, VP of programmatic ecosystem growth and innovation at RTB House.
With FLEDGE, it’s clear who owns the data, who is responsible for the calculations and which entity is assigning users to an interest group. FLEDGE also makes it clear how and to whom data is being transferred.
“The concept is quite complicated,” Włodarczyk said. “But, frankly speaking, it needs to be in order to provide the right privacy guarantees.”