[billybob]

> 1) ones that give you what you want > 2) ones that drive demand

A big part of Google's success is that #1 is much easier to prove than #2.

"People bought our product more because they had become familiar with it over the last month via newspaper/radio/Facebook ads" is a hard-to-prove claim.

"We got X clicks from Google ads leading directly to Y purchases" is much easier.