What is an affiliate tracking cookie?

thankx guys it helped me a loti have a spyware terminator, and it helped me to deleted but every time i'm online there is this affiliate on my pc, so boringIt is a small code that is placed on a computer to track purchases made from affiliate sites. For example: Buyer visits affiliate site describing wonderful cookies available at XYZ cookies. Buyer clicks on Affiliates web page link and is taken to XYZ's Bakeries, where they purchase those wonderful cookies. A cookie was place on Buyers computer, saying purchase was made through Affiliates web site, so XYZ can send money to Affiliate for helping with your purchase.