backdraft7 - 2:15 pm on May 18, 2013 (gmt 0)
From personal experience, it usually leads to a handful of "go getter's" who won't read your TOS and feel they have free reign to scrape your content to build their own wordpress versions of your pages in less than desirable neighborhoods. As ted said, it can work for giants, but for small sites, listen to netmeg.
I ran my affiliate program for almost 10 years, but closed it down just last month. Not worth the added drag.