Payment Conventions

* CPM (Cost Per Thousand) is paying for exposure of their message to a specific audience.
* CPV (Cost Per Visitor) is paying for the delivery of a Targeted Visitor to the advertisers website.
* CPC (Cost Per Click). In this scheme, an advertisement may be displayed (and assumedly viewed) many times, but the advertiser pays based only on the number of user clicks.
* CPA (Cost Per Action). In this payment scheme, the publisher takes all the risk of running the ad, and the advertiser pays for the media on the basis of only the number of users who complete a transaction, such as a purchase or sign-up.
* Cost per Conversion describes the cost of acquiring a customer, typically calculated by dividing the total cost of an ad campaign by the number of conversions.

http://en.wikipedia.org/wiki/Online_advertising