CPUM stands for Cost Per Unique Mille, which means the cost per 1,000 unique impressions. Unlike traditional CPM (which counts every impression), CPUM only counts one impression per unique user, regardless of how many times the same person sees the ad.

This model is designed to provide more accurate reach and fair pricing, especially for advertisers who want to avoid paying multiple times for the same viewer.

For publishers, CPUM can be beneficial if your traffic consists of a large number of unique visitors rather than repeat views. It rewards fresh traffic more than repeated page loads from the same users.
Key differences between CPM and CPUM:

CPM: Counts every impression (including repeats)
CPUM: Counts only unique users (one impression per user)

CPUM is a great middle-ground model for advertisers who want both reach and efficiency without overpaying for repeated impressions.
Have you tried CPUM campaigns? Do you prefer it over traditional CPM?