http://www.xbiz.com/article_piece.php?cat=44&id=7544
Interesting Read...and true....i especially like this paragraph :
Regardless of the program, payout type, or the way in which you send it traffic, what you really want to do is look at the actual checks you receive from the sponsor ? after all, this is the bottom line. Savvy webmasters will count their own clicks, meaning, they will use a script that records the number of clicks on any particular link to a sponsor, and divide the actual amount of the check they receive by the number of clicks they sent. This gives you the payout per click of a particular sponsor given the realities of your particular traffic. Relying on sponsor stats is a no-no, because each sponsor counts clicks in a different way, so the only way for you to determine what works best with your traffic is to count clicks yourself, that way you can compare the profitability of different sponsors using a common baseline