A two-tier affiliate program is a way to earn money in affiliate marketing by promoting products and recruiting others to do the same. In the first tier, you earn a commission when someone buys through your affiliate link, just like in a regular affiliate program. The second tier is where it gets interesting: you also earn a smaller commission when people you've referred to the program, called sub-affiliates, make sales. This setup encourages you to promote the product and invite others to join the program. It can help you earn more by building a network of affiliates under you. However, it requires effort to find good sub-affiliates who will actively promote the products. I think it's a great way to boost income if you're good at networking. What are your thoughts on this structure?