We look at writing a script quite differently from the rest, and add marketing benefits that the others haven't thought of yet. Affiliates have unlimited amount of tracker IDs so they can track their advertisements. Real-time statistics for your affiliates on everything. The tracker IDs are also passed when a sale is made. This means affiliates can track which ad gets the most sales.
Affiliates can view stats by the day.
Shows the referring URLs and how many hits each got. Affiliates can add tracker notes so they can be reminded which ad was for what. Affiliate area runs off a header and footer file which you can edit in the admin. So your affiliate program will not look like everybody else's. Affiliates can add a short code to the end of their referral URL and send traffic to different product pages.