European Unified ID (EUID)
In practice, for a UK buyer
The paragraph above is the neutral answer. This is the part a vendor glossary leaves out.
The intended bridge from a customer list to premium inventory under UK and EU data protection. To be exact about its state here: AdBuyMCP's CTV compiler emits an empty EUID audience list, so no compiled plan carries one today, and the adapter is explicitly non-transacting pending an operator agreement. Anyone reading elsewhere that we target CTV on EUID should know that identifier reaches no plan yet.
What this one connects to
Most confusion in media buying comes from two adjacent terms being used interchangeably, so these are the neighbours worth reading next.
Unified ID 2.0 (UID2)
An open-source, consent-based advertising identifier derived from a hashed email or phone number, developed as an industry alternative to third-party cookies. EUID is its European counterpart.
First-party data
Data an organisation has collected directly from its own customers and visitors — a CRM list, purchase history, site behaviour. Distinguished from third-party data by the existence of a direct relationship with the person it describes.
Mobile advertising ID (MAID)
A resettable identifier assigned by a mobile operating system to a device, used to recognise the same device across apps for advertising. Apple's IDFA and Google's advertising ID are the two that matter.
Identity resolution
The process of deciding that two different identifiers refer to the same person or household, so that behaviour seen under one can be joined to the other.
More on targeting and identity
How an audience is described to a seller, and how much of the description survives. Most of the honest difficulty in media buying lives here.
45 minutes. Bring a real brief and we compile it live. You describe one audience and watch it compile into seven targeting specifications, each with the score for how much of the definition survived.
Talk it through