While these models have diminished in mature e-commerce and online advertising markets they are still prevalent in some more nascent industries. China is one example where Affiliate Marketing does not overtly resemble the same model in the West. With many affiliates being paid a flat "Cost Per Day" with some networks offering Cost Per Click or CPM.
Amazon has spent years perfecting the art of online selling and you’ll learn a lot about online marketing by observing how they do it. They constantly test different ways of promoting products and have evolved their site quite a lot over the years. See what widgets they use to promote related products, watch how they use reader reviews, and see the way that they describe products.