Cost Per Action Marketing, also known as Cost Per Acquisition Marketing, is a style of online affiliate marketing where publishers (affiliates) receive a commission when a specific action is completed by a third party as a direct result of their marketing. The specific action could be the submission of an email address or a telephone number in order to receive some free information or product. Alternatively it might be an action such as the filling out of a form, signing up to receive a newsletter, agreeing to receive a quotation etc. CPA marketing differs from mainstream affiliate marketing in that usually (but not always) the third party is not required to make a purchase – i.e. commissions normally are based on lead generation.