Prebid’s New ID Gives Publishers Much-Needed Control Over Their Data

The identifier combines Epsilon’s PubCommon ID, which is based on publisher first-party data, with the sharedid.org ID, which is based on third-party cookies. While it still partially relies on third-party cookies, SharedID acts as a starting point to test and develop an identity solution that gives publishers more control as the industry at large evaluates other initiatives and products, such as Google’s Privacy Sandbox and The Trade Desk’s Unified ID 2.0.

Tom Kershaw, chairperson of Prebid and chief technology officer of Magnite, said building something that still supports third-party cookies allows publishers to manage the transition to first-party data offerings as the web trackers dwindle.  

“The main goal of this is to allow segment creation to move out of the DSP into the SSP, where we can allow publishers to securely interact with each other without leaking that ID into a device graph,” Kershaw said.

SharedID, which is open source, is meant to complement other identity products by addressing instances where no personal data, such as an email address or phone number, is available, when a user doesn’t log into a website or when a publisher chooses not to pass such login information to the buy-side.  

Many ID products rely on user information gathered from publishers, which is then obfuscated and passed to buyers. For example, The Trade Desk’s Unified ID 2.0, one of the most noteworthy post-third-party-cookie identifier, will rely on email addresses and offer publishers a sign-on product to help collect that data.

However, the vast majority of internet users don’t log in to every website they visit. Roughly 5% of the open web is authenticated, according to data from Permutive, a publisher-focused data management platform.

With SharedID as a common identifier among Prebid’s members, it should reduce the need for cookie syncing and create common audience segments for buyers. It will also allow publishers to choose which entities, like a DSP, can receive its ID and transact on it.

“There can be a singular ID that at least creates some better level of consistency across sites,” said Paul Bannister, chief strategy officer of CafeMedia, adding that reducing the number of cookie syncs will also help webpages load faster.

Stephanie Layser, vp of advertising technology at News Corp, said SharedID acts as a foundation toward building a better version of the current digital supply chain.

“I think right now, there’s a lot of like concentration on rebuilding the ecosystem that already exists, and not a lot concentration on creating a better, safer ecosystem for users,” she said.

Publishers have long called out ad tech’s practice of taking their data from the bidstream and using it without their consent or gain. They’ve also the floated idea of having an independent governing body to ensure such behavior doesn’t happen with Unified ID 2.0, another open-source initiative.

Bannister said some amount of sharing publisher data can help marketers scale out their buys, capturing and leaking of publisher data has devalued media owners’ inventory.

“Publishers are saying in the future world, we want to have more control over how that data is used, where it’s used, what it’s used for, how often it’s used and how the collective we are compensated for it, too,” he said.

Other companies that announced their support of SharedID include Business Insider, Publishers Clearing House, MediaMath, Adform and Zeta Global.