Cost per mille requires only that the publisher make the advertising available on his or her website and display it to the page visitors in order to receive a commission. Pay per click requires one additional step in the conversion process to generate revenue for the publisher: A visitor must not only be made aware of the advertisement but must also click on the advertisement to visit the advertiser's website.
Another difference is that with affiliate marketing business, an affiliate can sell different products all at the same time. His selling potential is limitless. Even if the products are not related to one another, he can still do affiliate marketing. He only needs to create a separate website to market different products. Unlike with offline middleman marketing, a middleman must only sell related products to maintain his credibility, for who would take a salesman seriously who sells cars and baby products at the same time?