Cost Per Action (CPA) is a cost model where affiliates are compensated upon a user taking a desired action, such as buying a product, completing a lead form, or subscribing to a service. This is a popular model with advertisers who desire measurable results and a tangible return on investment since they only pay for the successful action. Affiliates also like CPA offers for their ability to generate greater revenue, especially when promoting to likely-to-converge audiences.