Project Rearc – Everything You Need To Know

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While dependency on third-party cookies has been the norm for tracking and identifying users to deliver targeted ads for decades, it is slowly becoming phased out. A growing lack of support for the use of these cookies is threatening the viability of the ad delivery sector, and is thus a major issue among industry players.

In response to this problem, the IAB has launched “Project Rearc,” a worldwide project to bring stakeholders from the digital advertising and media distribution chain together to re-architect digital marketing in a unified effort to protect personalization and consumer privacy.

What Is Project Rearc?

Project Rearc is a worldwide effort founded by the IAB Tech Lab in 2020 to “re-architect” the digital advertising industry. As part of the initiative, the group is coming together to create new accountability and addressability standards for the industry, with consumer privacy at its core.

Project Rearc is a worldwide call-to-action for stakeholders across the digital supply chain to rethink and re-architect digital marketing in order to support core industry use cases while maintaining consumer privacy and customization.

Project Rearc Is About Standards


Project Rearc propagates the notion that it’s essential to maintain user level addressability in order to build and continue trust in the industry. It aims to achieve this through the consistent demonstration of accountability and adherence to users’ privacy and data rights.

The IAB Tech Lab’s Rearc Accountability Working Group to develop technical solutions that support compliance programs.

Four areas of work are collaborating to create an industry-wide accountability structure:

Global Privacy Framework: This framework will standardize the recording and propagation of consumer privacy preferences across markets, making it easier and more efficient for all industry participants to comply with changing regulations.

Accountability Program Guidelines: These will be the standards of conduct that organizations seeking access to identifiers and personal data must follow in order to obtain it.

Technical Mechanisms And Auditable Data Structures: All data sent in the supply chain must be tamper-proof, traceable and auditable to verify that user privacy preferences have been maintained.

Attestation Framework: Continuing automated testing to detect incorrect or criminal non-compliance by industry participants.


Navigating the future of addressability is a major component of Project Rearc’s work, along with enhancing industry accountability. Third-party cookies will eventually be eliminated, resulting in a consumer ecosystem with authenticated ‘logged in’ users with consumer-approved data, as well as anonymous users with little or no data.

Addressable and authenticated users

There are several areas of the internet where users willingly sign in or submit identifiable data to gain access to information and services; and there are a variety of publishers that have made the switch. Project Rearc is focused on developing industry standards that will allow for responsible use of these user-provided identifiers across a secure supply chain. There are several business approaches accessible to the market, all of which are focused on placing a high bar on user privacy and accountability. Authenticated user standards will allow third parties to act on behalf of trusted first parties without giving way to unauthorized third-party tracking and data gathering.

Non-addressable and anonymous users

With more non-addressable audiences and an expanding role in the overall marketing mix, contextual targeting is becoming increasingly important.

When there is no identification available to third-parties, standardization will be implemented to establish categorization standards and contextual signals in the bidding process for scale in buying and selling.

First-party data and audience attributes

Project Rearc is investing in standards that would allow publishers with first-party data on their audiences to make audience attributed information available in the bidding process if no ID is available to third parties. As a result, publishers will be able to scale their data and provide value to their audiences. is one of the key organizations that Tech Lab is working with on these projects.

Is Project Rearc Proposing An ID Based Solution?

Project Rearc’s purpose is to establish new technical guidelines that define privacy-preserving addressability, with the end goal of enabling fast, secure and transparent media buying inventory in a manner where consumers can choose which ads they want to receive. Standards will allow for contextual buying and selling without the use of third-party cookies, which will be eliminated with the arrival of GDPR. Project Rearc is not proposing an ID-based solution, but rather developing industry standards that will allow for responsible use of authenticated user identifiers across a secure supply chain.

What’s Happening Now?

The removal of third-party cookies and identifiers will have a significant influence on digital advertising stakeholders, and Project Rearc is centered around establishing the groundwork for tomorrow’s ad targeting, measurement, and optimization solutions.

Since project launch, it has collaborated with PRAM (the Partnership for Responsible Addressable Media), which brings together business, policy, and technical efforts from a wide range of industry stakeholders.

The IAB Tech Lab has also been leading a collaborative approach to educate member and non-member stakeholders about the initiative, as well as to allow worldwide input on new technical standards and guidelines that promote “privacy by default” addressable advertising and measurement.

It has welcomed and encouraged the many critical business and policy discussions that are presently happening among all stakeholder groups involved in the process, and are offering a number of ways for teams to globally participate in the conversation. From policy, business, and technology perspectives, Project Rearc is aiming to implement inclusive and applicable standards across the sector.

In this effort, the IAB Tech Lab has hosted a series of Project Rearc Webinars to provide additional information on next steps, as well as how to get involved in the process.

What’s Next?

The Project Rearc initiative is ongoing, and the IAB Tech Lab is committed to working with industry stakeholders to establish guidelines that preserve user privacy while promoting a healthy and sustainable digital advertising ecosystem.

Project Rearc is an ongoing project that aims to bring stakeholders across the online advertising supply chain together with industry experts, academics, and publishers to establish guidelines that will promote responsible data usage within the digital advertising ecosystem.

Project Rearc is considered an important undertaking that is necessary in order to preserve the health of the online advertising ecosystem in the wake of ever-evolving privacy laws. By establishing new technical guidelines that define privacy-preserving addressability, Project Rearc will allow for fast, secure, and transparent media buying without the use of third-party cookies.

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