If the rate of cost to the ecommerce sites is right for the number of extra sales, it'd spread like wildfire (with the right sales calls). I think there's real

If the rate of cost to the ecommerce sites is right for the number of extra sales, it'd spread like wildfire (with the right sales calls). I think there's really two models here. Refer a product and refer a site. Refer a site would be a prime target for the long-tail, especially if you only charge them on a successful sale (not just a referral submitted). On the other hand, a system to implement refer a product would fit in well for the mid-sized sites. And if it gains any traction, the big sites are your exit strategy. Get acquired for the technology so they don't have to spend the money to develop it in house. I'd probably start with the refer the site, charge based on a percentage of an extra sale, then later integrate refer a product.