The Internet has increased the prominence of affiliate marketing. Amazon popularized the practice by creating an affiliate marketing program whereby websites and bloggers put links to the Amazon page for a reviewed or discussed product to receive advertising fees when a purchase is made. In this sense, affiliate marketing is essentially a pay for performance marketing program where the act of selling is outsourced across a vast network.
In corporate law and taxes, an affiliate is a company that is related to another company, usually by being in the position of a member or a subordinate role, a subsidiary. According to Investopedia, a subsidiary is a company "whose parent is a majority shareholder." (That means the parent owns 51 percent or more of the other company's shares of stock.