Clickbank

ClickBank is a huge marketplace for digital products that:

1. Allows vendors to sell electronic products (mostly ebooks) without a merchant account
2. Allows affiliates to promote these products and earn commissions

Currently, Clickbank has over 100,000 affiliates and promotes over 10,000 products, making it one of the largest affiliate networks on the Internet.

Commission Junction

Commission Junction, founded in 1998 and acquired by ValueClick in 2003, is one of the largest affiliate marketing channels on the Internet. Their advertisers - the merchants that sell products or services online - are relatively bigger and better-developed companies. Generally, this means the products and services that the publishers - affiliates - promote have better quality.

Google Affiliate Network

 Are you surprised that Google has its very own affiliate network? I know I was when I came across it. This is not something Google came up with overnight. The affiliate network originally came from Performics which was acquired by DoubleClick. In turn, Google bought out DoubleClick and eventually inherited Performics which got renamed to Google Affiliate Network.