The biggest strength Clickbank have had over the majority of the 3rd party payment processors out there is their built in affiliate program.

It looks as if there will be a new contender in the affiliate program stakes: 2Checkout.

2Checkout are currently discussing and planning adding an affiliate program to their system, and they’re inviting you to have your say:

http://www.2checkout.com/community/?p=354

This is ground-floor stuff, so any requests you make have a better chance of being added into the system.