Cost per action/sale methods require that referred visitors do more than visit the advertiser's website before the affiliate receives a commission. The advertiser must convert that visitor first. It is in the best interest of the affiliate to send the most closely targeted traffic to the advertiser as possible to increase the chance of a conversion. The risk and loss are shared between the affiliate and the advertiser.
One of the reasons I like Wealthy Affiliate is because it enables me to provide this blog for free to people, but also be able to sell a genuinely high-quality product that I know is always updated and provides a better service than I ever could. Plus, when people sign up using my affiliate link, I can still provide one-on-one coaching and support as a way to add value and as a “thank you” for signing up using my link. Wealthy Affiliate truly is a win-win-win setup.