The use of pay per click (PPC/CPC) and pay per impression (CPM/CPT) in traditional affiliate marketing is far less than 1% today and negligible. CPM and CPC are today still heavily used in display advertising and paid search.
Cost per mille (thousand) (CPM/CPT) requires the publisher only to load the advertising on his website and show it to his visitors in order to get paid a commission, while PPC requires one additional step in the conversion process to generate revenue for the publisher. Visitors must not only be made aware of the ad, but also pursue them to click on it and visit the advertiser's website.
Cost per click (CPC/PPC) used to be more common in the early days of affiliate marketing, but diminished over time due to click fraud issues that are very similar to the click fraud issues modern search engines are facing today. Contextual advertising, such as Google AdSense are not considered in this statistic. It is not specified yet, if contextual advertising can be considered affiliate marketing
