Charlene Li was quoted in mediapost suggesting that marketers should seek to test the effects of their campaigns and understand the experience and reactions of people to those keywords, rather than only looking at the numbers.
I agree in principle, and it remains true that if you are going to talk to a conference of search marketers, you have to temper your words a bit so you don't lose the attention of the people who spend their days in an Excel/SQL driven quest to "optimize" their keyword buys or ad targeting.
Finding out what keywords drive the most revenue for your business is an interesting challenge and one that many businesses need to do. But at the end of the day, you'll find me building a relationship with a customer, not the keywords that he types into Google or Bing or ...Bing :).
Those relationships are about more than keywords, they are about an experience and delivering value. As more businesses shape up to this reality, they are sure to reap the rewards. As I have been chronicling in my Human Marketing series, I think creating a connection with a customer, even during short transactions, is what delivers long term value to the enterprise.