annej - 10:36 pm on Jun 26, 2006 (gmt 0)

even use a customized "call to action" to encourage conversions.

In that case I imagine the cpa type ads would be in different units and treated quite separately.

While call to action would hurt the advertiser in pay per click, writing something about how great the product is or how it would be a good purchase based on the article on the page makes sense for PPA.