AdTech learned a new term in 2024–ID Bridging. When a direct identifier from cookie sync or device ID for advertising is not available, ID bridging may be used to make an assumption about, or determine, who the user is via a different method. It came to light that identifiers from this practice were being passed in the `buyeruid` and/or `ifa` attributes in OpenRTB.
Those two attributes (user.buyeruid and device.ifa) are critical in DSP decision algorithms so, while ID Bridging isn’t inherently untoward, many buyers understood these fields to have a different meaning. This brought forth heavy discussion in the AdTech ecosystem about the expectation of values in the abovementioned fields.
Since sunlight is the best disinfectant, IAB Tech Lab spun up a workstream of over 80 participants across 40 companies focused on updating the OpenRTB 2.6 specification. The goal was to add clarity around the appropriate use of the attributes in question, and determine where and how to transparently signal use of identifiers when `buyeruid` and `ifa` weren’t the correct location. This became an exercise in clarifying existing values and adding new ones to the Extended Identifiers Object.
A full overview of the changes can be found in the 2.6 GitHub Repository, but here is a high-level summary:
- Update the attribute descriptions of `buyeruid` and `ifa` to clearly state the expected default behavior.
- A 3-page description of what exactly is meant by ‘Cookie Syncing’ to remove any ambiguity.
- Updated `source` attribute description to reference the canonical domain of the party that created the Extended Identifier.
- New attributes (inserter, matcher, mm) in Object: EID to give information about the party that put the EID into the bid stream, the party that did the bridge, and enumerate the different kinds of bridging scenarios (as listed in the attributes associated AdCOM list).
- And because we’re nice (and want to do everything we can to help increase adoption), a TON of Implementation Guidance showing how to use the new signals in different scenarios.
The telemetry these updates provide will be powerful signals facilitating the most appropriate evaluation of these IDs in the bidstream.
Hillary Slattery
Sr. Director, Programmatic, Product Management
IAB Tech Lab