Affiliate Marketing, in its most simplistic description can be explained like this: 

An affiliate tracking software gets hooked up to the merchant’s shopping cart. Then, the affiliate manager finds other websites and newsletters with people who would be interested in the merchant’s products. Those other websites run ads/links advertising the merchant. When a consumer clicks the link, they go to the merchant’s website.

If the consumer makes a purchase, then the tracking software notes it. The affiliate earns a percentage of the sale for every sale they bring the merchant. So, it’s simply a virtual sales force for the merchant’s business. 

Affiliate Marketing is all about referral sales … sales that are generated as a direct result of an affiliate’s efforts to market the merchant’s product or services.

Affiliates do all the marketing up to and including, leading the potential client to the merchant’s website. But, it’s 100% up to the merchant to convert that lead into a sale.

If the merchant pays affiliates based on the actual sales they generate, then be forewarned that affiliates will be looking at the merchant’s website for its sales conversion potential.