Originally Posted by BigFurry

Amazon is actually super easy to sell. It's one of the most trusted websites that your visitors already shop at. Sometimes you send them to a link to buy a pack of clothespins, and they also add 20 sacks of dog food to the cart. :-) The hard part is getting traffic for it of course.

There is truth to what Richard says, but there are also some other factors to consider.

- affiliates also bring in tons of invisible sales through improving the brand's visibility

- the 80/20 may be true, but there's also a long tail for the rest of the affiliates.
ie. a lot of small affiliates can bring in a big amount of sales when combined

- it's not always easy to tell who the best affiliates will be, in advance, especially for a new program owner

As someone on the board said, the affiliate model is one of the cheapest methods to have hundreds or thousands of people working on figuring out what the best way is to market your product. Through lots of different channels - some that you will never think of yourself.
And you only have to pay them a commission when they're successful.