Personalization is as old as marketing itself. Give each customer what they want, how they want it, when they want it. New technologies, platforms, and devices give us the tools to reinvent this venerable approach, expanding its reach and effectiveness. To wring the maximum value out of personalization, you have to track your results, constantly re-evaluate what you are doing, and adjust your strategy accordingly. In Part One of this 5-part series on personalization, we'll start with the broad strokes.