This is a great video from a panel during Affiliate Summit. The five ladies holding the discussion have decades of combined experience and they provide some really great info.
If you're considering starting an affiliate program for your business or your product then this is recommended viewing.
The Top Five Affiliate Management Myths Debunked.
One of the best takeaways:
If your site is not already primed to convert visitors to buyers, then affiliate traffic will NOT increase your revenue.