One of the reasons that it's so successful is because the program is free and extremely simple to join. The interface is also easy to use. This means that you can start earning money right away once you've signed up. You earn money when a customer clicks on one of the links you're promoting and then buys something on the site. It doesn't even necessarily need to be the product you've recommended.
Can you make money with affiliate marketing? The short answer is yes, affiliate programs can earn a extra money and even a full-time income from home. The long answer is a little more complicated. Like any home income venture, success comes not so much from what you choose to do to make money, but whether or not you do what needs to be done correctly and consistently.