gregbo - 12:31 am on Mar 29, 2006 (gmt 0)

I have thought CPC is a bad business model for over ten years. I was not surprised at all to see the first click fraud problems emerge in the mid-1990s. Undesirable aspects of CPC include a lack of accountability when either click fraud or some other disputed billing issue emerges (how does one "prove" that one received traffic); an inability to distinguish "legit" traffic from that which is generated by compromised computers (or fraudulent clickers), especially when it does not convert; paranoia on the part of publishers who can't discuss their publishing businesses with friends or family for fear that they'll click on the ad-bearing sites and get the publishers dropped from CPC programs; ever-increasing costs borne by publishers, advertisers, and SEs to detect, correct, and/or refund accounts that may have received "invalid" clicks.

I'm more in favor of CPM (where the impressions are determined statistically, not merely counted as the number of requests to deliver an ad from an ad server, or the number of times an ad shows up on a browser page).