"Analyzing Customers, Best Buy Decides Not All Are Welcome"—Headline/Wall Street Journal/11.08.04.
Best Buy has classified 100 million of its 500 million annual customer visits as "undesirable." And it aims to quash the "devils," by the likes of cutting promotions and pruning mailing lists, and supporting its "angels" with a better and better array of Cool (& Expensive) products.
Best Buy is not alone. There's a heap of research that supports dumping underperforming customers. (And some counter research.) Fact: It's easier done than said—and untold, lasting damage can follow for doing it gracelessly!