What are impressions?
Impressions are the number of times ads were shown.
What is CTR?
The CTR -Click-Through Rate- is obtained by dividing the number of clicks on an ad by the number of impressions
What is eCPM?
eCPM is calculated by dividing total earnings by total number of impressions in thousands. It is a great performance measure for your various ad units, you can use eCPM to compare your results amongst different networks.