Cost per click was more common in the early days of affiliate marketing but has diminished in use over time due to click fraud issues very similar to the click fraud issues modern search engines are facing today. Contextual advertising programs are not considered in the statistic pertaining to the diminished use of cost per click, as it is uncertain if contextual advertising can be considered affiliate marketing.
The best way to think about affiliate marketing is quality over quantity. There are a lot of small websites that will promote your product, but the key is finding a small number of partners that will deliver conversions. For example, an equity management services firm has over 20,000 affiliates in its system, but only about 25 affiliates generate 85 percent of revenue. https://businessinsightsbiz.tumblr.com/