Affiliate Marketing: Affiliate marketing is the practice of using a third party to market a company's products. It's a performance-based form of marketing that rewards the third parties with commission every time they sell one of the company's products. These commissions may be a flat rate per sale or a percentage of each sale. Affiliates may also be paid for every visitor or customer they bring in.

Affiliate marketing consists of four main components: A merchant or retailer that provides the product or service, the affiliate or publisher that places the advertisement, the network that connects them, and the customer who buys the product or service.

The market has become complicated over the years by affiliate management agencies, third-party vendors and super-affiliates.

Affiliate marketing often overlaps with other internet marketing techniques like SEO, PPC, content marketing and display advertising, though affiliate marketing is often less traditional. Affiliates may post product reviews, or use social media to promote a service.

Affiliate marketing is not the most common tool used by traditional advertisers, but it does play a major role for many online retailers. Still, traditional methods like email-marketing, search engine optimization and web design remain more popular in the world of online marketing.