That is an estimated of your earnings for 1 000 impressions. For example: If you earn 8 $ for 8000 impressions, then your eCPM would be 1 $. Got it?
I just had someone from Kontera email me this morning about setting up their CPC on my blog. They said that they campaigns seeing $1-4 CPC. Is this just a small percentage that they use to get you in, and then you just get cents?