ePCM means "effective cost per thousand ad impressions".
It is calculated by the below equation:
eCPM = [earnings/ad impressions] * 1000
I give you an example:
If your ad is shown 500 times and your earning is $3.50, then your eCPM is
[3.50/500]*1000 = 7
So, for thousand ad impressions, you will get $7.
The equation is simple, the more eCPM you have, the more $$ you will get.
There are a few tips which will increase your eCPM very well. I will reveal them in my next posts.
If you want to increase your adsense CTR, placing ads inside or between blog posts will definitely increase your revenue.