Its interesting and informative In simply we can say that affiliate marketing is a marketing practice in which a business rewards one or more affiliates for each visitor or customer brought about by the affiliates own marketing efforts.
Well that all depends on how much you want to work for it. If you decide to work hard enough to get somewhere with this you can earn good amount of money. But there are ups and downs, so you need to work hard to get to your goals.
It varies from person to person. If you treat affiliate marketing like serious business then you'll receive rewards accordingly. However if you do affiliate marketing for the sake of 'just another' source of income then you'll get nowhere. Focus is the key to success.