2 Answers

http://en.wikipedia.org/wiki/Affiliate_marketing

Basically, it is a model in which you award your customers for bringing new customers through referrals.

I think one of the easiest ways to earn money online is through affiliate marketing. Affiliate marketing means promoting other people’s products and earning a commission in return. I would like to share some tips for making money with affiliate marketing.
1. Create a website or blog.
2. Choose relevant product or services.
3. Find the product to promote.
4. Choose the right merchant.
I would also like to share an online tutorial which is useful for newbies who need to start with an affiliate program. You can check out http://www.openwebsitetutorials.com/category/featured-articles/, where they provide information regarding how affiliate marketing works and how to promote affiliate products.