Not necessarily, but a blog is really the best promotional tool. With that said, you can always use methods such as PPC or advertising to promote a product. This is another popular method to grow in affiliate marketing. For me, the best way to make the most out of affiliate marketing opportunities is to have a blog. Learn how to start a blog here.
Affiliate marketing is commonly confused with referral marketing, as both forms of marketing use third parties to drive sales to the retailer. The two forms of marketing are differentiated, however, in how they drive sales, where affiliate marketing relies purely on financial motivations, while referral marketing relies more on trust and personal relationships.