This famous marketing guru tells how to create a differentiation strategy specifically for the mass market, segmented markets, micromarkets, and—the latest evolution—individual markets of just one customer.

Marketing has been defined by some as the art of getting and keeping customers. Much of marketing has been cast around the “getting” problem. We have neglected the “keeping” problem. Keeping requires some thought; it goes beyond what the customer service department does. It gets into how...