Definition
CPM is what you pay for 1,000 ad impressions. It is a market-temperature metric: CPMs spike in Q4, in competitive auctions and in expensive geographies. Rising CPM with flat CTR means creative must work harder per impression.
Why it matters
You cannot negotiate CPMs, but you can out-create them. Hook strength is the lever that beats auction inflation.
Formula
Ad spend / Impressions x 1,000
All glossary terms