migriffin - 6:51 pm on Jun 21, 2006 (gmt 0)
SNAP.com has been doing this for about a month already. It works well, but I certainly see how the publisher will actually make much less. It will, however, minimize problems due to click fraud, which is more rampant in the contextual advertising arena. As an advertiser, I'd definitely sign up for CPA ads. As a publisher, I will definitely try the CPA model, but be hesitant to replace an already successful program with one that is too dependent on the quality of the landing page, checkout system, pricing etc.