
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.
Contact us
Latest posts

If you've ever sat in a meeting and heard an AdTech term you didn’t understand, you’re not alone. The industry evolves as quickly as a café turns over tables on a busy weekend. Even seasoned regulars can get tripped up by the jargon. So instead of scratching your head over the “menu,” let's walk through some of the most common terms: served café-style. The ingredients: The many flavors of first-party data Every meal starts with ingredients, and in AdTech, those ingredients are data. First-party data is not just one thing: it's more like everything your favorite neighborhood café knows about you. First-party data The café knows your coffee preferences because you've told them directly; whether by ordering at the counter, calling in, or placing an order online. This is information you’ve willingly provided through your interactions, and it belongs only to that café. First-party cookies The barista writes down your preferences in a notebook behind the counter, so next time you walk in, they don’t have to ask. First-party cookies remember details to make your experience smoother, but only for that café. Authenticated identity A loyalty app that connects online orders to in-person visits. By logging in, you're saying, “Yes, it's really me.” Authenticated identity is proof that the customer isn't just a face in line, but someone with a verified profile. Persistent identity Recognizing you whether you order through the app or in person. Persistent identity enables the ability to keep track of someone across different touchpoints, consistently, without confusing them with someone else. Permissioned data Agreeing to join the loyalty program and get emails. Permissioned data is a connection to the customer that the customer proactively shared with the café by signing up for their loyalty program or email newsletter. Each piece comes from direct interactions, stored and used in different ways. That's what makes first-party data nuanced. The saga of third-party cookie deprecation and changing privacy regulations makes it important to understand which types of data you can collect and use for marketing purposes. And once you have those ingredients, the next step is making sure you recognize how they fit together, so you can see each customer clearly. That’s where identity resolution comes in. The recipe: Bringing the ingredients together with identity resolution At the café, identity resolution is what helps the staff recognize you as the same customer across every interaction. Without it, they might think you’re two different people; one who always orders breakfast and another who sometimes picks up pastries to go. Matching The café has a loyalty program, and the pet bakery next door has one too. When they match records across their two data sets, they realize “M. Jones” from the café is the same person as “Michelle Jones” from the bakery. That connection means they can activate a joint promotion, like free coffee with a dog treat, without either business handing over their full customer lists. In marketing, matching works the same way, linking records across data sets for activation so campaigns reach the right people. Deduplication Collapses duplicate profiles into a single, clean record, so you don't get two birthday coupons, even though that would be nice to get. That's what Experian does at scale: we connect billions of IDs in a privacy-safe way, so you can get an accurate picture of your audience. And once you can recognize your customers across touchpoints, the next challenge is collaborating across systems and partners for deeper insights. That's where the behind-the-counter processes come in. Behind the counter: Crosswalks and clean rooms At a café, these terms are like the behind-the-counter processes that keep everything running smoothly. They may sound technical, but they all serve the same purpose: helping data collaborate across different sources, while keeping sensitive information safe. The goal is a better “meal” for the customer, deeper insights, better targeting, and more personalized campaigns. Here's how they work. Crosswalks The café partners with the pet bakery next door. They both serve a lot of the same people, but they track them differently. With a crosswalk, they can use a shared key to recognize the same customer across both businesses, so you get a coffee refill, and your dog gets a treat, without either one handing over their full customer list. A crosswalk is the shared system that lets both know it is really you, without swapping personal details. It's the bridge connecting two silos of data. Clean rooms The café and the pet bakery want to learn more about their shared customers, like whether dog owners are more likely to stop by for brunch on weekends. Instead of swapping their full records, they bring their data into another café’s private back room, a clean room, where they can compare trends safely and privately. Both get useful insights, while customer details stay protected. That’s a clean room: secure collaboration without exposing sensitive data. Of course, sharing and protecting data is only part of the picture. The real test comes when you need to serve customers in new ways, especially as the industry moves beyond cookies. Serving customers in new ways: Cookie-free to ID-free Targeting has evolved beyond cookies, just like cafés no longer rely only on notebooks to remember regulars. ID-free targeting The café looks at ordering patterns, like cappuccinos selling on Mondays and croissants on Fridays, without tracking who's ordering what. Instead of focusing on who the customer is, the café tailors choices based on the context of the situation, like time of day or day of the week. This is like contextual targeting, serving ads based on the environment or behavior in the moment, rather than on personal identity. ID-agnostic targeting The café realizes customers show up in all sorts of ways: walk in, online ordering, delivery. Each channel has its own “ID,” a name on the app, a credit card, or a loyalty profile. ID-agnostic targeting means no matter how you order, the café can still serve you without being locked into one system. Just like cafés no longer rely only on notebooks to keep track of regulars, marketers no longer have to depend solely on cookies. Today, there are multiple paths, cookie-free, ID-free, and ID-agnostic, that can all help deliver better, more relevant experiences. But even with new ways to reach people, one big question remains: how do you know if it’s actually working? That’s where measurement and outcomes come into play. Counting tables vs. counting sales At the café, measurement and outcomes aren't the same. Measurement Tables filled, cups poured, specials ordered. Outcomes What it all means: higher revenue, more loyalty sign-ups, or increased sales from a new promotion. Both matter. Measurement shows whether the café is running smoothly, but outcomes prove whether the promotions and strategies are truly paying off. Together, they help connect day-to-day activity to long-term success. All of this brings us back to the bigger picture: understanding the menu well enough to enjoy the meal. From menu to meal In AdTech, there will always be new terms coming onto the menu. What matters most is understanding them well enough to know how they help you reach your business goals. Just like at the café, asking a question about the specials isn’t foolish. It’s how you make sure you get exactly what you want. The more we, as an industry, understand the “ingredients” of data and identity, the better we can cook up new solutions that serve both brands and consumers. After all, the goal isn't just to talk about the menu, it’s to enjoy the meal. At Experian, we help brands turn that menu into action. From identity resolution to privacy-safe data collaboration, our solutions make it easier to connect with audiences, activate campaigns, and measure real outcomes. If you're ready to move from decoding the jargon to delivering better customer experiences, we’re here to help About the author Brandon Alford Group Product Manager, Experian Brandon Alford is a seasoned professional in the AdTech ecosystem with a focus on identity, audience, measurement, and privacy-forward solutions. He has spent his career helping advertisers and publishers navigate the complexities of digital advertising and privacy, bringing a practical and forward-looking perspective to industry challenges and innovation. AdTech jargon FAQs What is first-party data, and why is it important? First-party data is information a customer shares directly with a brand, like purchase history, preferences, or sign-ups. It’s the most valuable and privacy-safe data marketers can use to build personalized campaigns. How do identity resolution and matching work in marketing? Identity resolution ensures a brand can recognize the same customer across different touchpoints. Matching links records across data sets (e.g., between partners) so campaigns reach the right people without exposing full customer lists. What’s the difference between a crosswalk and a clean room? A crosswalk bridges two data systems with a shared key to recognize the same customer, while a clean room allows partners to analyze data together securely without exposing sensitive details. What does “cookie-free” or “ID-free” targeting mean? Cookie-free and ID-free targeting shift focus away from tracking individuals, instead tailoring ads based on context (like time of day or content being viewed) or allowing flexibility across multiple IDs. How is measurement different from outcomes? Measurement tracks activity (like clicks or visits), while outcomes prove business impact (like sales, loyalty, or revenue). Both are essential, but outcomes show whether strategies are truly effective. How does Experian help marketers with these AdTech challenges? Experian provides tools for identity resolution, privacy-safe data collaboration, and campaign measurement, helping marketers move from understanding the “menu” of AdTech terms to achieving real results. Latest posts

Holiday shopping in 2025 feels a lot like a complicated relationship. Shoppers want deals, but they also want trust. They start shopping early, but they’re still browsing well into December. They love the convenience of online shopping, but they still show up in-store before making the final call. Our 2025 Holiday spending trends and insights report, created this year in collaboration with GroundTruth, explores these contradictions. Our findings show that this year’s holiday season isn’t about one big shift; it’s about managing the push and pull between what consumers say, what they do, and how marketers respond. Here are three complicated truths you need to know. Experian's 2025 Holiday spending trends and insights report Optimize your 2025 holiday shopping campaigns with our latest report with GroundTruth. Download now 1. The new rules of holiday timing Almost half (45%) of consumers plan to start shopping before November, but 62% admit they’ll still be buying in December. And post-holiday shopping (think gift card redemptions and deal-hunting) remains a real factor. Why it’s complicated The holiday calendar isn’t what it used to be. There’s no single “big moment” anymore. Instead, shoppers are spreading purchases across months, peaking around the “Turkey 12” (the 12 days surrounding Thanksgiving) and again in the final December rush. What to do about it Stretch your campaigns across the full season, not just Cyber Week. Refresh offers to stay relevant as shopper motivations change from deal-seeking to last-minute urgency. Watch for post-holiday momentum and extend your promotions into January. How belVita nailed the timingIn celebration of National Coffee Day, belVita partnered with GroundTruth on a one-month campaign to boost product awareness and drive foot traffic to Target stores. By utilizing digital out-of-home (DOOH) and mobile ads powered by location, behavioral, and purchase-based targeting, the campaign achieved a 3.44% visitation rate, nearly $476k in products added to carts, and a low cost-per-visit of just $0.22. 2. Online leads, but in-store still seals the deal Nearly 40% of shoppers say they’ll split their purchases between online and in-store and 80% of consumers still prefer the in-store experience. Only a small fraction plan to shop exclusively in one channel. That means while digital often starts the journey, the final decision often happens in a physical store. Why it’s complicated Shoppers love the convenience of browsing online, but they still want the reassurance of seeing, touching, or testing products before buying. In-store isn’t just about the transaction, it’s the validation step. What to do about it Build omnichannel strategies that connect digital discovery with in-store follow-through. Use location and identity data to tie digital impressions to real-world actions, like foot traffic and purchases. Focus on consistency: shoppers expect the same value, tone, and trust whether they’re on a website, in an app, or standing in a store aisle. How Duke Cannon used on-premise targeting to drive sales liftDuke Cannon, a premium men's grooming brand, partnered with GroundTruth to launch a successful multichannel campaign utilizing location-based and behavioral audience targeting across CTV and mobile screens to drive in-store visits and sales. By targeting consumers with mobile ads while they were physically in-store, the company capitalized on high purchase intent, aiding in the 12% sales lift. This strategic approach resulted in over 43.9k provable in-store visits and a significant increase in sales. 3. Marketers double down, consumers hold back This holiday season, expectations are split. 66% of marketers expect holiday spend to rise, but only 22% of consumers agree. While brands are leaning into bigger investments across CTV, retail media, and social, shoppers are staying cautious, weighing value and waiting for the right deal. Why it’s complicated That disconnect introduces risk. If marketers don’t align spend with real consumer behavior, budgets can get wasted in the rush to cover every channel. Shoppers haven’t stopped spending, but they're spending differently. They’re trading down to discount and big-box retailers while cutting back in discretionary categories like apparel and restaurants. What to do about it Prioritize efficiency by focusing on the right audiences, not just more impressions. Make consistency your advantage: reach people once and connect across platforms instead of chasing fragmented signals. Balance aggressive media investment with messaging that acknowledges consumer caution — shoppers want value and trust, not hype. Measuring TV and streaming impact with iSpotiSpot’s Audience Builder, powered by Experian’s Marketing Attributes, helps brands reach high-value audiences. During the holiday season, a luxury retailer could target $100K+ households with affluent lifestyle interests. With iSpot’s Unified Measurement platform, they can track performance across linear TV and streaming and shift spend in real time to maximize results. The bottom line on 2025 holiday shopping trends This year’s holiday shopping season is, well…complicated. Shoppers are cautious but still engaged. They’re early planners and last-minute browsers. They want the ease of digital, but the confidence of in-person. For marketers, the opportunity lies in embracing that complexity, not trying to simplify it away. The brands that balance relevance, trust, and convenience across the full season and across every channel will be the ones that win. Download our full 2025 Holiday spending trends and insights report to explore all five shifts shaping this season and see how you can turn complexity into opportunity. Download About the author Fred Cheung Director, Partnership Sales, Audigent, a part of Experian Fred Cheung has spent over a decade in the programmatic advertising space, with roles at Mindshare, Jounce Media, Twitter, and The Trade Desk. His deep experience in trading and product management helps in his current function on the Experian Marketing Services’ Sales team where he focuses on data growth and adoption across the industries’ leading buy-side platforms. 2025 holiday shopping trends FAQs Why is holiday shopping in 2025 described as “complicated”? Because consumer behavior is full of contradictions. People will shop earlier but also later, browse online but purchase in-store, and want deals while demanding trust. Marketers need to navigate these push-and-pull dynamics. When do most shoppers plan to start their holiday shopping? Nearly half (45%) say they’ll start before November, but 62% admit they’ll still be buying in December, with momentum even continuing into January through gift card redemptions and deal-hunting. What role do physical stores still play in holiday shopping? Although many consumers begin online, the majority still make their final decisions in-store. In-person shopping acts as a validation step where customers can see, touch, or try products before buying. How should marketers adapt their strategies to shifting holiday timing? Instead of focusing only on Black Friday or Cyber Week, marketers should stretch campaigns across the full season, refresh offers frequently, and continue promotions into January. Are marketers and consumers aligned on holiday spending expectations? Not entirely. 66% of marketers expect spending to rise, but only 22% of consumers agree. Shoppers are cautious, prioritizing value and often trading down to discount or big-box retailers. What’s the best way to connect online discovery with in-store sales? An omnichannel approach using identity and location data can bridge digital impressions with real-world actions like store visits and purchases, ensuring consistency across touchpoints. What can brands learn from the case studies in the report? Brands like belVita and Duke Cannon successfully tied digital campaigns to in-store results by utilizing precise audience targeting, location data, and well-timed promotions. Where can I get the full insights report? You can download Experian’s 2025 Holiday spending trends and insights report to explore all five shifts shaping this season. Latest posts

We spend our days surrounded by screens: at work, at home, and everywhere in between. But audio is the one channel that moves with us, from morning routines to evening commutes, from workouts to household chores. More than two-thirds of U.S. consumers will listen to digital audio every month this year, making it one of the fastest-growing ways to connect with audiences. Experian and Audacy are working together to solve the challenges of fragmented listening, cross-platform targeting, and campaign measurement, helping brands reach people in the moments other channels can’t. Why audio sticks with us Audio fits into life’s in-between moments, from the commute to the workout to the chores, when other media can’t. Unlike video, it doesn’t demand full attention; it joins the flow of daily routines. This makes audio uniquely personal, creating connections that other formats can’t replicate. Audacy’s expertise in understanding listener behavior ensures that audio campaigns feel like a natural part of daily life. Experian's data helps advertisers identify the right audiences, while Audacy ensures the message is delivered at the right time. Together, we help brands create campaigns that resonate deeply with listeners. By meeting audiences in their moments of focus, audio becomes a powerful tool for building meaningful and lasting connections. "Audio is a companion in people’s daily rituals. Whether it’s doing dishes, folding laundry, or going for a run, you have audio going in your ears, and you’re really engaged with it. From an advertising perspective, that’s incredibly powerful because listeners are paying attention to the content.”Kevin Greenwald, SVP of Advertising and Audience Products Making sense of scattered listening habits Today’s listeners consume audio across a variety of devices and platforms. Devices like smart speakers and smart home hubs now account for over 27% of digital audio time spent daily among U.S. adults, highlighting the growing role of connected devices in audio consumption. When listeners bounce between apps, stations, and devices, it’s easy for advertisers to lose track of them. Audacy’s advanced platform capabilities, combined with Experian’s identity solutions, simplify this process by providing a unified view of audience behavior, ensuring campaigns remain cohesive. Audio is highly adaptable, letting advertisers tweak a message on the fly by shifting tone, length, or format to stay relevant in the moment. This flexibility ensures that campaigns remain cohesive and impactful, no matter where or how listeners engage. “Audio has a degree of flexibility that other channels don’t. You’re not tied to a programming clock, and ad lengths can vary. It’s also easy to create a great audio ad quickly, which makes it a channel ripe for experimentation and innovation.”Kevin Greenwald, SVP of Advertising and Audience Products Following listeners wherever they go Today’s listeners don’t stay in one place: they bounce from live radio in the morning to streaming music during the day, then wind down with a favorite podcast at night. For advertisers, that creates a challenge: how do you keep up with an audience that’s always moving? Without a unified view of the listener journey, campaigns can lose impact. With the right insights, though, every handoff becomes an opportunity to stay relevant and connected. Audacy’s platform, combined with Experian’s identity solutions, bridges these gaps. Together, we help you follow your audience wherever they go, creating consistent experiences that drive results. This approach improves targeting and ensures that messages remain impactful. "I hope that there’s a day coming where we can understand ad exposure in the car as well as more cars are connected and things like that. That would be really powerful."Kevin Greenwald, SVP of Advertising and Audience Products Your audience is listening, let's make sure they hear you Audio helps you connect with your audience in moments other channels miss. With Experian’s marketing data and Audacy’s expertise, you can simplify cross-platform targeting, improve campaign measurement, and create messages that truly resonate. Let’s work together to make your message heard. Let's talk audio strategy. Contact us today About our experts Kevin Greenwald SVP of Advertising and Audience Products, Audacy Kevin Greenwald is the SVP of Advertising & Audience Products, where he partners closely with Audacy's sales team to deliver leading ad product and measurement capabilities for their clients. Crystal Jacques VP of Enterprise Partnerships, Experian Crystal Jacques is the VP of Enterprise Partnerships, leading Experian's go-to-market team across all verticals. With over ten years of experience in the Identity space, Crystal brings a wealth of expertise to her role. She joined Experian in 2020 through the Tapad acquisition, following her successful stint as the head of Global Channel Partnerships for Adbrain, which The Trade Desk later acquired. Latest posts