There is an interesting new arrangement where merchants can easily launch a referral (Refer a Friend) program on their confirmation page, which is powered by an affiliate. The service is called SimpleSocial from SocialFeet.
The merchants pay an affiliate commission for new sales made through the links placed in Facebook, Twitter, or email.
SimpleSocial is currently live on dozens of sites, including Ecko, Paul Fredrick, DHC, and TechForLess.
Networks partnered with SocialFeet include buy.at, Commission Junction, Google Affiliate Network, LinkShare, and Pepperjam.
More details at http://www.socialfeet.com.