Affiliate marketing is a web-based marketing practice in which a business rewards one or more affiliates for each visitor or customer brought about by the affiliate's marketing efforts.

Affiliate marketing is also the name of the industry where a number of different types of companies and individuals are performing this form of internet marketing, including affiliate networks, affiliate management companies and in-house affiliate managers, specialized 3rd party vendors, and various types of affiliates/publishers who promote the products and services of their partners.

Affiliate marketing overlaps with other internet marketing methods to some degree, because affiliates often use regular advertising methods. Those methods include organic search engine optimization, paid search engine marketing, email marketing and in some sense display advertising. On the other hand, affiliates sometimes use less orthodox techniques like publishing reviews of products or services offered by a partner.

Affiliate marketing — using one site to drive traffic to another — is a form of online marketing, which is frequently overlooked by advertisers. While search engines, e-mail and RSS capture much of the attention of online retailers, affiliate marketing carries a much lower profile. Still, affiliates continue to play a significant role in e-retailers' marketing strategies. Guide to E-Commerce Technology, 2007-08 Edition by Internet Retailer