Great article by Scott Allan is LinkShare’s vice president of marketing. Some quotes from the article:

There are several factors driving the increased interest in performance marketing. The three biggest drivers are the rise in affiliate deal sites, advances in technology and the overall evolution of affiliate marketing. These influences are prompting strategic online retailers to increase their intellectual and financial investments in the affiliate channel.
Interestingly, a December 2011 report from Forrester Research finds that consumers perceive deals offered on affiliate sites as superior to those on the merchant’s website. Even when the offers are the same, the conversions are more likely to come through the affiliate sites.
Today’s affiliates are well versed in SEO and are focused on providing valuable content that draws readers in and brings them back. Guest posts from celebrities, exclusive site deals, and the ability to quickly swap out ads that are dated or not effective for a particular market segment further boost traffic and site stickiness.
Entire article here: