A CPA (cost-per-action) network means just what its name suggests. It is an Affiliate Network in which a commission of the sale is paid on the actions performed. These actions not only include sales or revenue sharing as in the case of other Affiliate Networks, but also getting a lead such as e-mail address, credit card number, telephone number or getting an order for the product, a sign-up or a download from the website.
from Internet and Businesses Online: Affiliate Revenue Articles from EzineArticles.com