Pay Per Click vs. Pay Per Sale
Just a look at the problem from the side of an affiliate program. Definitely, we prefer to pay on the "per sale" basis. Otherwise very soon you will be cheated by some dishonest partners who'll be generating absolutely worthless traffic. So, you'll have to pay less for all clicks, including those which are good. This way what economists call "adverse selection" is being created.
But maybe there are some strong pro-s for the Pay Per Click system?
Can you share your experience with both?
Best regards, Seopharmacy