Eurydice - 4:57 am on Apr 13, 2009 (gmt 0)
Adwords is extremely complex. There are many factors and there is an interplay between them.Google hasn't documented most of it. The vast majority of users overpay substantially. We work with large advertisers; they have teams of people and large agencies, and they still don't understand it. For medium or small advertisers, there is very little chance that they'll understand it.