Identity in AdTech: Meet The Various ID Solutions

AdTech Industry

Identity in AdTech: Meet The Various ID Solutions


In recent years, we have seen a quick proliferation of various standardized ID solutions. The consortiums and companies that stand behind them include some of the leading AdTech vendors, promising a better alternative to cookie syncing and competition with walled gardens like Facebook and Google.

Why Does Online Advertising Need an ID Solution?

The need for a standardized ID results from a number of problems AdTech faces:

1. Being able to identify users as they move around the web is vital for everyone in the online advertising industry.

Publishers earn more money on their inventory, advertisers are able to achieve better campaign performance, and AdTech companies are able to sell their tech.

2. Web browsers don’t emit a persistent ID.

Mobile devices like smartphones and tablets emit a persistent device ID – it only changes if a user manually resets it.

AdTech companies can access this device ID during ad requests for in-app inventory, making it easier for advertisers to identify and target users as they move between apps.

Web browsers (on laptops, desktops and mobile devices) don’t have a persistent ID, which is why AdTech companies create third-party cookies to identify users on different websites.

3. Identifying users on web browsers is done via third-party cookies.

The problem with third-party cookies is that they are increasingly blocked or deleted by ad-blocking software, browser settings (think Apple’s ITP and Firefox’s Enhanced Tracking Protection), manually deleting cookies, or browsing in private/incognito mode. 

4. Domains other than the one that created the cookies cannot read them.

A DSP cannot read or access a cookie set by an SSP, which makes identifying the same user difficult and creates technical complexities when running behavioral and retargeting campaigns.

5. To solve this problem, AdTech companies use a process known as cookie syncing.

This process works by matching the cookie IDs of one AdTech vendor with another. Read more about cookie syncing here.

6. Cookie syncing is a resource-intensive and slow process.

Hundreds of web calls are made with every page load, which impacts page loads and the user experience. 

7. Cookie syncing is not always reliable.

The match rate of cookie IDs between different AdTech and MarTech platforms typically varies between 40–60%, and as the number of platforms involved in the syncing increases, the match rates decrease. 

8. Walled gardens like Google and Facebook have the advantage of using deterministic data, e.g. login data tied to people-based IDs.

Programmatic vendors still rely on cookies, resulting in many advertisers and publishers turning to the walled gardens due to the advantages they offer in terms of identity, tracking and targeting.

Enter the need for a standardized ID solution.

Current ID Solutions

Currently, there are a handful of ID solutions that help solve cookie-syncing and identity issues and compete with the walled gardens.

The Trade Desk’s Unified ID

The Trade Desk, a market-leading demand-side platform (DSP), aims to decrease the number of cookie syncs conducted on web pages by allowing other DSPs, SSPs, and DMPs via their Unified ID. 

TTD uses its and domains to power the ID-resolution service across web-browser environments (i.e. web and mobile web browsers). 

Since launching the service, TTD has seen cookie match rates of 99% with its trial partner, Index Exchange. 

A list of The Trade Desk's Unified ID partners
A list of TTD Unified ID’s main partners

The Trade Desk is also a member of the Advertising ID Consortium (see below).

The Trade Desk’s Unified ID 2.0

In July 2020, The Trade Desk revealed that it would be releasing a new version of it’s Unified ID solution (2.0).

Because of the growing decline of third-party cookies in popular web browsers like Safari and Firefox, and soon in Google Chrome, the new iteration will replace the use of third-party cookies with encrypted email addresses. 

This newer version of Unified ID is open source and can be used by all companies, not just those working with The Trade Desk.

DigiTrust ID

DigiTrust is a neutral, industry-wide organization that began as a spinoff of the IAB cookie-standardization working group in 2014 to solve the identity problem in AdTech. 

DigiTrust became part of the IAB once again after its acquisition by the IAB Tech Lab back in April 2018. It now operates as one of the IAB Tech Lab’s working groups, allowing both DigiTrust and IAB members access to its encrypted and standardized ID. 

Decryption is only available to members of the consortium who are part of regulatory programs and uphold consumer-privacy standards. DigiTrust maintains policies which prohibit its members from passing on the decrypted persistent ID to non-members.

Platforms on the buy side pay a fee to use the service, which goes towards helping support the technical infrastructure that powers the DigiTrust ID.

A list of the IAB Tech Lab and DigiTrust ID's partners
The main partners of the IAB Tech Lab & DigiTrust ID.

Recently, DigiTrust joined forces with another ID solution – the Advertising ID Consortium. The collaboration aims to standardize one of three domains: AppNexus (Advertising ID Consortium), The Trade Desk (Unified ID), and DigiTrust. 

Being a neutral, vendor-agnostic organization, DigiTrust differentiates itself from other ID initiatives. This is a huge selling point for the programmatic partner platforms, which, for specific business reasons, would rather avoid using a standardized ID from a vendor-owned domain like the ones offered by The Advertising ID Consortium and The Trade Desk.

Goodbye DigiTrust ID

In June 2020, the IAB Tech Lab announced that it would be shutting down DigiTrust due to the ongoing decline of third-party cookies, which underpin DigiTrust ID.

Advertising ID Consortium

The Advertising ID Consortium is an open and independent group governed by representatives from AdTech companies like Index Exchange, LiveRamp, The Trade Desk and dataxu, and boasts the support of a number of other ad platforms. 

The Advertising ID Consortium utilizes cookie IDs (TTD’s Unified ID and DigiTrust’s ID) and their own cookie ID via AppNexus’s domain, as well as people-based identifiers supplied by LiveRamp’s IdentityLink (IDL)

The latter allows publishers to generate a unique user ID without having to rely on cookies, which is a great advantage at a time when third-party cookies (and even first-party cookies) are becoming less available because of ad-blocking tools and privacy features in web browsers.

The video below explains how the Advertising ID Consortium works.

While the consortium is constantly adding new partners, it has lost others in the process. AppNexus, one of the founders of the group, left shortly after it was acquired by AT&T. MediaMath departed the Advertising ID Consortium as well in 2018, reportedly due to disagreements about the direction of the ID solution. 

This exposes an inherent problem with initiatives like the Advertising ID Consortium’s ID and Unified ID – its individual members are often competitors, and issues associated with governance, payment structure and trust sometimes may stop them from easily settling for a single standard. 

Although AppNexus did retire from its leadership role in the consortium, it is not planning to take away its domain, which suggests continued availability of the AppNexus cookie ID for the consortium’s members.

A list of the Advertising ID Consortium's partners
The main partners of the Advertising ID Consortium


French-based startup, ID5, also offers an independent ID solution, known as Universal ID, that works in a very similar way to the open solutions mentioned above. 

ID5 allows publishers, data providers and AdTech companies to outsource their cookie-syncing processes with their partners and use ID5’s cookie-matching table. 

In July 2019, ID5 announced that Universal ID is available in Prebid.js, allowing publishers and AdTech vendors to utilize the ID in header-bidding auctions. 

Over 45 AdTech vendors have partnered with ID5, including Adform, Beeswax, Mediamath and Smart.

A list of ID5's partners

Flashtalking Identity Management

Flashtalking, a leading ad-management and analytics-technology company, also offers a solution to the ID problem with FTrack. 

FTrack is a cookie-less tracking solution that incorporates data from different devices and across the web and mobile apps. The result is a probabilistic ID that can be used to not only target audiences, but also to attribute conversions to campaigns.

Apart from FTrack, Flashtalking also provides other identity-management solutions, such as identity graph for cross-device, people-based marketing, IDconnect to unify data across different platforms, and IDconnect+ to provide model-ready data sets.

Strengths and Weaknesses of the ID Solutions


One main strength of TTD’s Unified ID and the Advertising ID Consortium is that they have a number of large AdTech players as members, meaning better compatibility and match rates between platforms.

For DigiTrust and ID5, their main strength is that they are independent, vendor-agnostic solutions — i.e. they use IDs that aren’t tied to an existing AdTech vendor, as is the case with Unified ID and the Advertising ID Consortium.


All the solutions face the same challenges — they still rely on cookies. 

Even though these solutions reduce the number of cookie syncs on a page, they are still impacted by ITP and other browser features (privacy settings and ad blockers). 

The exception to this would be the Advertising ID Consortium that uses LiveRamp’s people-based ID (as explained in the video above).

Other ID Solutions

Apart from the main solutions listed above, there is a handful of other companies providing their own ID services as part of their data onboarding services

Examples include Signal’s Customer Identity Solutions, LiveIntent, Neustar, Throtle, and Zeotap.

The main goal of these solutions is to piece together IDs from online and offline channels to create a centralized view of consumers, rather than to use these IDs for online media buying.

For example, Chicago-based SaaS company Signal connects brands with customers at scale through real-time, continuous data onboarding and identity resolution. Signal’s customer identity solution provides a platform for brands and data owners to address customers across multiple devices and channels in real time.

Signal helps brands build their own first-party identity graph, an asset that becomes more valuable over time as marketers wish to reach their customers 1:1 outside of walled garden ecosystems such as Facebook, Google and Amazon.

The Challenges Facing These ID Solutions

As with all initiatives in AdTech, adoption is often the biggest challenge. 

However, the need for an ID solution is paramount among independent AdTech companies, advertisers and publishers, so chances are adoption rates of at least one or more of the proposed ID solutions will rise over the coming months and years. 

Also, having multiple solutions to choose from – both vendor-owned and neutral – suggests that AdTech vendors will face less friction towards adoption.

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