The term “qualified sale” (or its synonym, “qualified purchase”) is important in the affiliate marketing context because the advertiser (the ecommerce merchant) defines in advance what constitutes a qualified sale. When an affiliate agrees to promote the merchant’s products, that affiliate is accepting the merchant’s definition of a “qualified sale.”
You should also make sure you aren't competing with your own affiliates for eyeballs. Any marketing channels you're using, such as search engines, content sites or e-mail lists, should be off limits to your affiliates. Put marketing restrictions into your affiliate agreement and notify partners immediately. It's your program--you set the rules. Or, if you prefer, you can let your affiliates run the majority of your internet marketing.