Perry Marshall on Google Adwords

I've always enjoyed Perry Marshall's emails about Google marketing, and this article is his best yet. Snippet:

"I have a friend named Brad who used to work at the rail yards in Western Nebraska. He would watch huge trains pass through the switchyard on their way from one coast to another, full of commodities like corn and soybeans and coal. One day he realized that just by watching the flow of commodities in the rail yard from day to day, he could figure out what the fat cats were doing on the futures markets. He used this "insider information" to buy futures and make money...Most people see trains. Brad sees money changing hands."