Spam is the biggest threat to organic search engines, whose goal is to provide quality search results for keywords or phrases entered by their users. Google's PageRank algorithm update ("BigDaddy") in February 2006—the final stage of Google's major update ("Jagger") that began in mid-summer 2005—specifically targeted spamdexing with great success. This update thus enabled Google to remove a large amount of mostly computer-generated duplicate content from its index.
Amazon Associates — Amazon sells millions of products (books, music, electronics, toys, and more) that fit into virtually any niche, so its affiliate marketing program is a natural choice for almost anyone. Comparatively speaking, its payouts are generous, too: They vary based on product type and sales volume, but commission rates start at 4 percent and can reach up to 15 percent for specific product lines. However, note that Amazon’s program is now illegal in several states (although there are some work-arounds).
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.