Welcome to the myhosting.com Forums.
How does a cost-per-action affiliate payment system differ from a cost-per-click system?
CPC or CPA: Which Leads to Better ROI? - iMediaConnection.com
CPM is a holdover from traditional media advertising, and does not take advantage of the Hypertext nature of the medium. It charges purely on the number of times the advertisement is served. It does account for branding effects, that are not accounted for in the other models. CPC is a cost associated with each click on the advertisement to the target page. CPA is a cost associated with each lead created from a click on the advertisement (CPL), or each sale (CPS). Both CPC and CPA are much more accountable means of developing a price for the banner, and either are also used for affiliate programs.