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.
There’s also a very direct and logical tie-in for affiliates; these sites inherently cater to, and attract, visitors who are in the market for a product or set of products (ideally at a discounted rate). It’s the goal of the companies that make these products to get as many people as possible to clip their coupons and eventually make a purchase; so they make affiliate payments to coupon sites who are able to help them achieve this goal.
3.4. You will be solely responsible for the development, operation and maintenance of your Site and for all materials that appear on your Site. We disclaim all liability for such materials. You shall indemnify and hold us harmless from all claims, damages and expenses (including, without limitation, attorney's fees) relating to the development, operation, maintenance and contents of your Site. You are also responsible for notifying us of any malfunctioning of the Required URLs or other problems with your participation in the Program in accordance with the terms of the Offer and this Agreement. BTI will respond in normal course to all concerns upon notification.
I went from making $20k in 2016 to $100k in 2017 by dropping my web design/SEO clients and doing affiliate marketing/blogging full-time. 90% of my (passive) affiliate income comes from SiteGround, a hosting company who awarded me affiliate of the month in July, 2017 when I made $9k in 1 month. Since then I’ve continued to hit numbers like this – the screenshot below is from March, 2018 when I made $14.5k in 1 month (just with SiteGround).