jpchrysler - 3:32 pm on Mar 29, 2006 (gmt 0)

I *really don't think PPC is going anywhere. It's market driven, so people will pay what they can afford. A pure conversion model cannot exist because much of the future growth of advertisers will come from late adopters - small businesses which cannot track conversions per se.

PPC is a shared risk, hybrid model already. I think in some niches, CPM and CPA will still be used forever, but CPC works pretty well.

Regarding click fraud, while it is a threat, it's a very manageable threat for the PPC industry. The impression or conversion fraud vulnerabilities in CPM or CPA models respectively may prove to be as great as those in the CPC space.