Affiliate marketing is a type of performance-based marketing in which a business rewards one or more affiliates for each visitor or customer brought about 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 to warrant a secondary tier of players, including affiliate management agencies, super-affiliates and specialized third party vendors.
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 (SEO), paid search engine marketing (PPC - Pay Per Click), e-mail marketing, and in some sense display advertising. On the other hand, affiliates sometimes use less orthodox techniques, such as publishing reviews of products or services offered by a partner.
Affiliate marketing is commonly confused with referral marketing, as both forms of marketing use third parties to drive sales to the retailer. However, both are distinct forms of marketing and the main difference between them is that affiliate marketing relies purely on financial motivations to drive sales while referral marketing relies on trust and personal relationships to drive sales.
Affiliate marketing is frequently overlooked by advertisers. While search engines, e-mail, and website syndication 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.
Affiliate marketing has grown quickly since its inception. The e-commerce website, viewed as a marketing toy in the early days of the Internet, became an integrated part of the overall business plan and in some cases grew to a bigger business than the existing offline business. In 2006, affiliates worldwide earned US$6.5 billion in bounty and commissions from a variety of sources in retail, personal finance, gaming and gambling, travel, telecom, education, publishing, and forms of lead generation other than contextual advertising programs.
In 2006, the most active sectors for affiliate marketing were the adult, gambling, retail industries and file-sharing services. The three sectors expected to experience the greatest growth are the mobile phone, finance, and travel sectors. Soon after these sectors came the entertainment (particularly gaming) and Internet-related services (particularly broadband) sectors. Also several of the affiliate solution providers expect to see increased interest from business-to-business marketers and advertisers in using affiliate marketing as part of their mix.
Websites and services based on Web 2.0 concepts—blogging and interactive online communities, for example—have impacted the affiliate marketing world as well. The new media allowed merchants to become closer to their affiliates and improved the communication between them.
Web 2.0 platforms have also opened affiliate marketing channels to personal bloggers, writers, and independent website owners. Regardless of web traffic, size, or business age, programs through Google, LinkShare, and Amazon allow publishers at all levels of web traffic to place contextual ads in blog posts.
Forms of new media have also diversified how companies, brands, and ad networks serve ads to visitors. For instance, YouTube allows video-makers to embed advertisements through Google's affiliate network.