Affiliate marketing is a type of performance-based marketing in which a business rewards one or more affiliates for each visitor or customer brought by the affiliate's own marketing efforts. The industry has four core players: the merchant (also known as 'retailer' or 'brand'), the network (that contains offers for the affiliate to choose from and also takes care of the payments), the publisher (also known as 'the affiliate'), and the customer. The market has grown in complexity, resulting in the emergence of a secondary tier of players, including affiliate management agencies, super-affiliates and specialized third party vendors.