The on-line advertising world has its own distinct nomenclature.

If you're new to the world of on-line advertising, you may want to read the following to help you understand terms that you're likely to come across.

...

Cost Per Acquisition is the cost per acquisition or action (for the advertiser) - that is, where the advertiser pays based the required action being performed after either clicking on an ad, or less commonly, after having seen an ad impression. For the publisher, this can also be thought of as the revenue per acquisition or action. .

eCPM

Effective Cost Per Mille is the effective cost per 1,000 impressions. By converting CPC and CPA rates back to an eCPM rate, campaigns of different cost models can be compared with each other to understand their relative performance. For the publisher, this can also be thought of as the effective revenue per 1,000 impressions.