This document provides an overview of affiliate marketing. It discusses how affiliate marketing works as a pay-for-performance model where affiliates are paid a commission only when they drive a sale or desired action for the merchant. It also outlines some of the key benefits of affiliate marketing programs such as being a win-win model for merchants and affiliates, providing predictable returns, and allowing merchants to outsource marketing efforts. However, the document also notes some potential problems such as loose control over how affiliates promote products and possibility of click or lead fraud.