Viewability
In practice, for a UK buyer
The paragraph above is the neutral answer. This is the part a vendor glossary leaves out.
A served impression and a viewable impression are different things, and the gap is where a meaningful share of digital budgets goes. Stated plainly: AdBuyMCP has no independent verification integration — no viewability, brand-safety or fraud vendor is wired in — and describes that as unbuilt rather than unnecessary.
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.
Proof of play
A seller-supplied record confirming that a specific advert played on a specific screen at a specific time, with the play logged rather than estimated. The out-of-home equivalent of an impression log, since a screen cannot report who was in front of it.
Evidence provenance
A label attached to a number recording how it was produced — reported by the seller, observed on your own property, estimated by a model, or established by a powered experiment — so its strength travels with it.
Working media
The portion of an advertising budget that actually buys advertising, as opposed to the portion consumed by platform fees, data costs, agency fees, ad serving and production. Usually expressed as a percentage of total spend.
More on measurement and evidence
What you can prove afterwards, and the difference between a number that means something and a number that does not.
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