By now it practically goes without saying that the marketing environment is undergoing tremendous change and that proliferation—of media, segments, and distribution channels—is the reason.¹

Marketers are responding. During 2006, for example, the 50 biggest US advertisers boosted their overall ad spending, and many experimented aggressively with newer tools, such as Web-based video, paid-search advertising, viral marketing, and social networking. In the aggregate, those same companies also reduced their spending on “measured” media, such as television, newspapers, radio, and Internet display ads.² Less visibly, senior marketing executives are rethinking the capabilities and operating approaches needed to confront proliferation successfully. Their degree of success will be critically important to CEOs and for companies as a whole.

We recently sat down with senior marketers from four companies—Carlsberg, Nokia, Wal-Mart Stores, and Yahoo!—that are facing different aspects of the proliferation challenge. Carlsberg, like many packaged-goods companies, is experiencing rapid market polarization as the low and high ends of its beer market grow more rapidly than the middle. Nokia is experimenting creatively with nontraditional media and turning out more new products than ever in response to fragmenting customer needs. Wal-Mart is segmenting its customers more finely than it has in the past...