Affiliate Marketing getting popular

What is affiliate marketing?

It is a mode of marketing where you pay your customers to bring more customers in. It is this simple. The philosophy behind is that if a person likes your product than his friends who must have tastes matching his/her would like it too. Thus the lead conversion odds are much higher as compared to normal marketing approaches.

How big is the market?
I was being told by an active internet based affiliate marketer friend of mine that it has grown to around $2 billion :O

If the two questions are basic and if they have initiated curiosity in you then you can visit Affiliate Marketing Forums - Revenue Source and can start something. You won't take much time to make money if you are good.