In September last year, the IAB Tech Lab released its ID Provenance Protocol to bring greater transparency to ID bridging as digital advertising moves beyond third-party cookies. Here, we look at what’s driving new identifiers, how ID bridging works, and what the protocol brings to the table.
Privacy becomes paramount
No-one needs reminding that the world is increasingly focused on user privacy. And while Google may have adjusted its plans to cull third-party cookies in Chrome, the advertising industry could be forgiven for feeling the path to targeted marketing is increasingly strewn with obstacles.
In a nutshell, digital advertising players face significant signal loss because they have no, or limited, third party data with which to enrich customer profiles or deploy in cross-channel and cross-device targeting. At the same time, advertisers are under growing pressure to deliver healthy returns on campaigns, which requires efficient ways to find and target the right audiences.
On the other side of the media trading table publishers are continually looking for ways to be creative in using their access to all-important first-party data to help them maximize their own revenues.
Paradoxically, this is played out in an environment where people are more connected than ever before. Digital devices provide a wealth of data signals that, deployed responsibly, can help the ad tech community serve users better.
ID bridging: A new tool…
This being the ad tech arena, there is, of course, a solution.
ID bridging is not new, but it has been pushed further into the limelight as the third-party cookie reaches its twilight years.
The topline definition is that ID bridging provides an alternative way to identify users without compromising privacy, thereby letting publishers offer addressability options to advertisers.
That's the theory, anyway.
In practice, it means that when an automated browser cookie sync isn’t possible, ID bridging can fill the gap. It recognizes a user regardless of the touchpoint or device and stitches this fragmented data together, creating a "bridge" to produce a single user profile.
But, as with every significant evolutionary step taken by the digital advertising industry, ID bridging has also been the topic of much debate, with reservations around the issue of transparency a particular concern. Specifically, a bridged cookie ID could not be explicitly declared as such, meaning that buyers ran the risk of innocuously treating it as a cookie ID obtained through legitimate cookie syncing. Along with the fundamental lack of transparency, this presented problems including inaccurate targeting, disrupted frequency capping, and attribution difficulties.
…and a new IAB protocol
This has seen the IAB Tech Lab, in line with its remit to enable growth and trust in the digital media ecosystem, add a new specification to the OpenRTB protocol. Released on 23 September 2024, the ID Provenance Protocol, is designed to address the challenges opened up by ID bridging.
Specifically, it introduces industry-wide standards around:
- The reliability and transparency of where identifiers were sourced (i.e. their ‘provenance’)
- How those identifiers are applied within the bidstream
- How buy- and sell-side partners should share IDs
To get more granular, this sees new fields added to the Extended Identifier (EID) object, a component of the OpenRTB specification that allows identifiers beyond cookie-based IDs to be used. These include:
- "inserter": Details who set the ID,
- "matcher": Lists who performed the bridging,
- "mm": Sets out the bridging methods used.
By shining a light on the source and method of retrieving a user ID, these provide explicit transparency that was not previously available.
The new protocol also updates the descriptions of the standard identifiers ‘buyeruid’ and ‘ifa’—both of which have become points of contention as ID bridging has gained traction—to clarify their legitimate use.
In effect, the IAB Tech Lab’s specification rubber-stamps ID bridging and will help to ensure that its role in digital advertising is recognized and progressed.
Data, analytics and matching: How ID bridging works
To better understand the standards laid out by the protocol, it’s useful to look more closely at how ID bridging works.
First-party data lies at the heart of ID bridging.
Second-party data can be used to enrich the organization’s first-party data and enhance targeting capabilities. But the privacy-first objective of ID bridging makes it essential that it's only sourced from trusted partners that are compliant with data protection regulations.
This data fuels complex algorithms. These undertake deterministic or probabilistic matching which, by analyzing various signals, link different browsing profiles to indicate that they are in fact one individual.
The deterministic method leverages user-consented identifiers where there is little doubt that they are linked to the individual: Name, hashed emails, login information, etc. While the method is highly accurate, this type of data can be difficult to acquire so this type of matching is hard to scale.
Probabilistic matching broadens the scope by analyzing signals such as IP addresses, type of device, and browsing behavior. It uses similarities and probabilities to assess the likelihood of multiple datapoints being the same person. It's less precise but offers wider reach.
The key for publishers is finding the right balance between accuracy and scalability.
Bridging benefits
ID bridging enables publishers to offer buyers the addressable audiences they require to deliver returns on advertising campaigns in a world in which third-party cookies can no longer be relied on.
In short, by retaining the ability to provide consistent targeting, it underpins the value of a publisher’s inventory in a privacy-safe landscape. It potentially offers the additional bonus of unlocking spend in Safari and Firefox browsers where the standard cookie process hasn’t been able to identify a user.
By adopting ID bridging and using the new IAB Tech Lab specification, publishers can also demonstrate their commitment to user privacy, as well as attract privacy-conscious advertisers.
For brands, the benefits lie in continued access to a targeted environment and therefore the ability to reach audiences for whom their offerings are relevant with messages that resonate. This is the lifeblood of effective advertising.
Privacy, accuracy and transparency concerns
But the course of programmatic never did run smooth—meaning it will come as no surprise that ID bridging does not necessarily offer a straightforward transition away from the use of third-party cookies.
First up, concerns around privacy are still firmly on the table. Hashed identifiers can be broken or reversed, compromising the anonymity of the user, while linking identifiers across platforms can introduce vulnerabilities and from there, data breaches. Guarding against these risks requires responsible handling of the data by all parties involved, as well as compliance with data protection regulations such as the GDPR and CCPA, which require transparency and user consent.
Next on the disadvantage agenda is accuracy, as outlined above when discussing probabilistic matching. Poor matching leads to poor audience targeting, and with that the knock-on effects of devalued inventory for publishers and low returns on campaigns for advertisers.
The third major issue is transparency. ID bridging is based on collecting and processing personal data, which automatically introduces the issue of whether the user has given explicit consent for their information to be deployed in this way. Many approaches to data gathering are ethical, but there are also practices in use that are questionable.
Looking ahead
Increasingly sophisticated requirements around user privacy mean the digital advertising industry needs to adapt to ensure it can deliver for publishers, advertisers and consumers. As third-party cookies head into the sunset, ID bridging is part of the new paradigm, offering as it does a viable alternative identifier to enable effective targeting.
However, while ID bridging offers some clear benefits, as is to be expected in a fast-paced environment, challenges remain.
Focused on privacy and transparency, The IAB Tech Lab ID Provenance Protocol provides a major milestone in resolving these issues, thereby helping to ensure the new IDs can deliver for both buy and sell side.
It also demonstrates the importance of the industry working together as it continues to develop. This ongoing commitment will be essential if ID bridging is to deliver on its potential and open new opportunities and revenue streams.
Working with BidSwitch
BidSwitch continually focuses on being at the forefront of this evolving industry so that we can meet the needs of our users and enable them to operate seamlessly. We have adopted the IAB Tech Lab specifications, and we are encouraging our partners—both supply and demand—to do the same.
Our guidelines around ID provenance have been drawn up to help the process and there is further detail about our solutions and the context for them in our webinar, Navigating Addressability: ID Bridging.
To discuss your journey to a cookieless environment, get in touch with the BidSwitch team today.