In most cases, the only reason an affiliate will send a viewer to a landing page is AdWords' strict rules about arbitrage, or some other rules set by the affiliate network. Google wants to provide its users with as good of content as they can manage, but they know affiliates are a large portion of their AdWords spenders. It's a delicate balance.

Many affiliates send users to landing pages or their own sites for their own tracking and data collecting purposes as well.

How do they get much organic traffic using just thin landing pages?