What counts as an impression?
An impression is recorded each time an ad is successfully delivered to a user's browser or device and a billable event fires. Impressions are the raw material of publisher revenue: your total earnings are, in simplified terms, impressions × eCPM ÷ 1,000. This means impression volume and eCPM together determine everything.
What is counted — and what is not
The dashboard shows only paid, valid impressions. The following are excluded:
- House ads and direct campaigns with no attached revenue
- Unfilled ad requests — where no buyer bid or no creative was available to serve
- Invalid traffic — bot activity, crawlers, and other non-human events filtered by OCM and its demand partners
- Impressions rejected during partner reconciliation after the fact
This filtering is applied both in real time and retrospectively, which is why impression counts from yesterday may decrease slightly when you check them the next day.
How to read impressions alongside other metrics
Impressions in isolation are less useful than impressions read alongside eCPM and earnings. The relationship between the three tells you what kind of change you are dealing with:
- Impressions down, eCPM steady → a traffic or fill problem. Your site is receiving fewer visits or fewer auctions are clearing.
- Impressions steady, eCPM down → a demand problem. Buyers are paying less for your inventory, but your traffic is fine.
- Both down → potentially a combination, or a single cause affecting both — worth investigating with your Account Manager.
- Impressions up, earnings flat → eCPM has fallen in proportion to the impression gain. More volume but lower quality demand.
You have 2,000,000 impressions and an eCPM of €0.50 — estimated earnings: €1,000. If impressions drop to 1,600,000 while eCPM holds at €0.50, earnings fall to €800. If instead impressions hold at 2,000,000 but eCPM drops to €0.40, earnings also fall to €800 — same outcome, completely different diagnosis.
- A sudden impression drop of 15–20% or more in a single day, with no corresponding traffic event on your site, is worth reporting to your Account Manager — it can indicate an ads.txt issue, a demand partner problem, or a header bidding configuration change.
- Check your Ads.txt Status widget on the Overview page whenever you see an unexplained impression drop — a missing or misconfigured entry can silently prevent buyers from bidding.
See also: Understanding eCPM · How your earnings are calculated · Understanding ads.txt and why it matters