adsense

8.14: web.care/empl/adsense/eCPM -- what exactly is that?

listed in your AdSense reports; it means,

"effective cost per thousand impressions."

by (dividing total earnings by total number of impressions )

times thousands.

It is a great performance measure for your various ad units,

so when experimenting, you can use eCPM to compare your results.