Hi,
Interesting fact i found today. It looks like some clickbank vendors use some kind of script that do the following thing:
if the visitor comes from no affiliate link, on the clickbank orderform is automaticly assingned some affiliate id from an array in the script. This means that every sale is made, theoreticly is made through an affiliate link witch leads to increase gravity wich leads to more affiliates...and so on.
Interesting, huh..?!?
So.. who know more about this?