
2024 marked a significant year. AI became integral to our workflows, commerce and retail media networks soared, and Google did not deprecate cookies. Amidst these changes, ID bridging emerged as a hot topic, raising questions around identity reliability and transparency, which necessitated industry-wide standards. We believe the latest IAB OpenRTB specifications, produced in conjunction with supply and demand-side partners, set up the advertising industry for more transparent and effective practices.
So, what exactly is ID bridging?
As signals, like third-party cookies, fade, ID bridging emerged as a way for the supply-side to offer addressability to the demand-side. ID bridging is the supply-side practice of connecting the dots between available signals, that were generated in a way that is not the expected default behavior, to understand a user’s identity and communicate it to prospective buyers. It enables the supply-side to extend user identification beyond the scope of one browser or device.

Imagine you visit a popular sports website on your laptop using Chrome. Later, you use the same device to visit the same sports website, but this time, on Safari. By using identity resolution tools, a supply-side partner can infer that both visits are likely from the same user and communicate with them as such.
ID bridging is not inherently a bad thing. However, the practice has sparked debate, as buyers want full transparency into the use of a deterministic identifier versus an inferred one. This complicates measurement and frequency capping for the demand-side. Before OpenRTB 2.6, ID bridging led to misattribution as the demand-side could not attribute ad exposures, which had been served to a bridged ID, to a conversion, which had an ID different from the ad exposure.
OpenRTB 2.6 sets us up for a more transparent future
In 2010, the IAB, along with supply and demand-side partners, formed a consortium known as the Real-Time Bidding Project for companies interested in an open protocol for the automated trading of digital media. The OpenRTB specifications they produced became that protocol, adapting with the evolution of the industry.
The latest evolution, OpenRTB 2.6, sets out standards that strive to ensure transparency in real-time bidding, mandating how the supply-side should use certain fields to more transparently provide data when inferring users’ identities.
What’s new in OpenRTB 2.6?
Here are the technical specifications for the industry to be more transparent when inferring users’ identities:
- Primary ID field: This existing field now can only contain the “buyeruid,” an identifier mutually recognized and agreed upon by both buyer and seller for a given environment. For web environments, the default is a cookie ID, while for app activity, it is a mobile advertising ID (MAID), passed directly from an application downloaded on a device. This approach ensures demand-side partners understand the ID’s source.
- Enhanced identifier (EID) field: The EID field, designated for alternative IDs, now accommodates all other IDs. The EID field now has additional parameters that provide buyers transparency into how the ID was created and sourced, which you can see in the visual below:

Using the above framework, a publisher who wants to send a cross-environment identifier that likely belongs to the same user would declare the ID as “mm=5,” while listing the potential third-party identity resolution partner under the “matcher” field, which the visual below depicts. This additional metadata gives the demand-side the insights they need to evaluate the reliability of each ID.

“These updates to OpenRTB add essential clarity about where user and device IDs come from, helping buyers see exactly how an ID was created and who put it into the bidstream. It’s a big step toward greater transparency and trust in the ecosystem. We’re excited to see companies already adopting these updates and can’t wait to see the industry fully embrace them by 2025.”
Hillary Slattery, Sr. Director, Programmatic, Product Management, IAB Tech Lab
Experian will continue supporting transparency
As authenticated signals decrease due to cookie deprecation and other consumer privacy measures, we will continue to see a rise in inferred identifiers. Experian’s industry-leading Digital Graph has long supported both authenticated and inferred identifiers, providing the ecosystem with connections that are accurate, scalable, and addressable. Experian will continue to support the industry with its identity resolution products and is supportive of the IAB’s efforts to bring transparency to the industry around the usage of identity signals.
Supply and demand-side benefits of adopting the new parameters in OpenRTB 2.6
- Partner collaboration: Clarity between what can be in the Primary ID field versus the EID field provides clear standards and transparency between buyers and sellers.
- Identity resolution: The supply side has an industry-approved way to bring in inferred IDs while the demand side can evaluate these IDs, expanding addressability.
- Reducing risk: With accurate metadata available in the EID field, demand-side partners can evaluate who is doing the match and make informed decisions on whether they want to act on that ID.
Next steps for the supply and demand-sides to consider
For supply-side and demand-side partners looking to utilize OpenRTB 2.6 to its full potential, here are some recommended steps:
For the supply-side:
- Follow IAB Specs and provide feedback: Ensure you understand and are following transparent practices. Ask questions on how to correctly implement the specifications.
- Vet identity partners: Choose partners who deliver the most trusted and accurate identifiers in the market.
- Be proactive: Have conversations with your partners to discuss how you plan to follow the latest specs, which identity partners you work with, and explain how you plan to provide additional signals to help buyers make better decisions.
We are beginning to see SSPs adopt this new protocol, including Sonobi and Yieldmo.
“The OpenRTB 2.6 specifications are a critical step forward in ensuring transparency and trust in programmatic advertising. By aligning with these standards, we empower our partners with the tools needed to navigate a cookieless future and drive measurable results.”
Michael Connolly, CEO, Sonobi
These additions to the OpenRTB protocol further imbue bidding transactions with transparency which will foster greater trust between partners. Moreover, the data now available is not only actionable, but auditable should a problem arise. Buyers can choose, or not, to trust an identifier based on the inserter, the provider and the method used to derive the ID. While debates within the IAB Tech Lab were spirited at times, they ultimately drove a collaborative process that shaped a solution designed to work effectively across the ecosystem.”
Mark McEachran, SVP of Product Management, Yieldmo
For the demand side:
- Evaluation: Use the EID metadata to assess all the IDs in the EID field, looking closely at the identity vendors’ reliability. Select partners who meet high standards of data clarity and accuracy.
- Collaboration: Establish open communication with supply-side partners and tech partners to ensure they follow the best practices in line with OpenRTB 2.6 guidelines and that there’s a shared understanding of the mutually agreed upon identifiers.
- Provide feedback: As OpenRTB 2.6 adoption grows, consistent feedback from demand-side partners will help the IAB refine these standards.
Moving forward with reliable data and data transparency
As the AdTech industry moves toward a cookieless reality, OpenRTB 2.6 signifies a substantial step toward a sustainable, transparent programmatic ecosystem. With proactive adoption by supply- and demand-side partners, the future of programmatic advertising will be driven by trust and transparency.
Experian, our partners, and our clients know the benefits of our Digital Graph and its support of both authenticated and inferred signals. We believe that if the supply-side abides by the OpenRTB 2.6 specifications and the demand-side uses and analyzes this data, the programmatic exchange will operate more fairly and deliver more reach.
Latest posts

Hi, Dana here with an update on my holiday shopping post from before Thanksgiving. Like I thought, I was able to get most of my shopping done that Black Friday weekend. It was all pretty fast and easy, but I did have one not so great experience too. My sister knew I was going to get something for my niece, so when she got an email from Toy World that everything would be 50% off on Black Friday she forwarded it to me to let me know. I was thrilled. I had done some searching for good toys this year and had some ideas. While I normally would shop online, the Toy World coupon said the 50% off was in-store only so I braved the crowds for a good deal. Unfortunately, when I got there I learned that the email was wrong – only select items were 50% off and others were buy one, get one 50% off. I was pretty upset because the hottest toys were the ones excluded from the deal. I came all that way based on the email. I wound up getting a gift, but I could have saved myself the hassle and long lines, especially since I didn’t get a deal that was different from any other day. That was a rough start to the shopping weekend, but, no worries, things improved. I have to tell you about my best shopping experience – I’ve been telling everyone! This year I used Pinterest to see what my mom has had her eye on lately. One of her pins is a food processor and I think that’s a perfect gift for her. I’m a card holder and reward member at Aaron’s department store and I know they carry some really nice kitchen appliances. They also happened to send me great Cyber Monday coupons in the mail – it was perfect timing. I went online on Cyber Monday, used the promo codes from the coupons and not only got great deals, but got free shipping too! How easy was that?! They also sent me shipping notifications so I knew exactly when to expect the package. I am really happy that I got something great for everyone on my list and now have time to enjoy the rest of 2012. I hope you enjoy it too! XOXO, Dana Editor’s note: You can tell that Aaron’s knows Dana. They used their direct mail piece to send her online offers because they know that’s her preferred purchase method. They’ve won her over once again and created a brand advocate. Learn where your company stands in your marketing efforts today, and how you can help move efforts forward to ensure your customers have good experiences like Dana had with Aaron’s, and avoid bad ones like her trip to Toy World.

With the busy holiday marketing season in full swing, Experian Marketing Services has released its online retail round-up for the week ending December 8. The online traffic to the top 500 retail sites increased 5% for the period of December 2 – 8, compared to the same week in 2011. Additionally, Amazon remained the top visited site among retailers, followed by Walmart and Target. The chart below includes the top 10 results: Experian Marketing Services also tracks top product searches. Listed below are the top 5 product searches for the week ending December 8: Uggs iPad mini iPad Beats by dre Ipod touch We will continue to publish weekly retail site data and insights through this holiday season. Please leave us a comment below if you have any specific questions along the way. Learn more about the author, Matt Tatham

Twenty years ago this week, the first mobile text message, or SMS, was sent by British engineer Neil Papworth. Today, Americans are texting more than ever and among young adults, many of whom were not yet born when the first message was sent, texting is almost as common a mobile activity as talking. And why wouldn’t it be? According to the latest Simmons National Consumer Study, 48% of adults ages 18-to-24 say that a conversation via text message is just as meaningful as a telephone call. A similar share of adults ages 25-to-34 feel the same way. Regardless of age, texting is still, technically, the second most common activity that Americans engage in on their cell phone after talking. During a typical week, 95% of mobile adults talk on their mobile phone, while 59% text. Among adults ages 18-to-24, however, 89% talk on their phone and 85% text. Despite the increasing availability of mobile chat or instant message applications, texting remains the dominant means for exchanging short messages. Only 8% of all mobile adults use their phone to IM or chat. The fastest thumbs To get a more in-depth understanding of the texting habits of adults today, we leveraged data from the Simmons Connect mobile panel of 1,485 U.S. smartphone owners. Hands down, young adults text more than any age other age group. During a typical month, in fact, smartphone-owners ages 18-to-24 send 2,022 mobile text messages and receive another 1,831 for a combined total of 3,852 texts sent and received. With every age bracket we move up, the number of mobile texts drops by roughly 40%. For instance, smartphone owners ages 25-to-34 send, on average, 1,110 text messages a month and receive another 1,130 for a combined total of 2,240 messages. We are also able to leverage the Simmons Connect smartphone panel to understand mobile calling behaviors. The data shows that while young adults hold the record for the most text messages sent and received, they actually make and receive few calls, by comparison. During a typical month, smartphone owners ages 18-to-24 make 119 calls on their mobile phone and answer another 64 calls. Adults ages 35-to-44 make and receive the most calls on their mobile phones in a given month. (Call counts do not include inbound and outbound calls that go unanswered.) Text around the clock Unlike television and radio, which have peak hours for reaching consumers, mobile text messages reach Americans throughout the day, providing advertisers with a medium to connect with consumers any time they want or need. No surprise, young adults are the most likely to send and receive mobile text messages throughout the day. The smartphone panel data shows that during every hour between 8:00 A.M. and midnight, more than half of young smartphone owners are both sending and receiving mobile text messages. Even when most of us are asleep, young adults’ smartphones continue buzzing from inbound texts. In fact, 37% of 18-to-24 year-old smartphone owners receive texts at 4:00 in the morning. By comparison, just 20% of smartphone-owners ages 25-to-34 years-old receive texts at this late (or early) hour as do 17% of those 35-to-44, 15% of those 45-to-54 and 10% of those ages 55 and older. Better to send or to receive? During overnight hours, the share of young smartphone owners who send texts surpasses the share who receives them. However, by 8:00 A.M., the difference between those two figures narrows to the point that they are nearly equal. In fact, from noon until 11:00 P.M., young adults are more likely to send mobile text messages than they are to receive them. Call or text? While texting is still a secondary use of mobile phones after calling, that’s not the case all day, especially among young adults. In fact, while smartphone owners ages 18-to-24 are more likely to make an outbound call than they are to send a text from their phone between 7:00 A.M. and 10:00 P.M., they are more likely to send a text between 11:00 P.M. and 6:00 A.M., during hours when they might understandably wake the recipient. That should help us all sleep a little better.