The affiliate glossary ↗AFFDude / Field notes
eCPM
In plain English
What does eCPM mean?
Effective cost per mille: revenue (or spend) per thousand impressions, used to compare traffic or placements priced on different models.
eCPM normalises everything to a per-thousand-impressions number so a CPC placement can be compared to a CPM one. For a publisher it is revenue per thousand impressions; for a media buyer it is what the thousand impressions actually cost after the auction. Ad networks optimise publisher eCPM, which is why fill rate and eCPM come up together.