I've always loved the phrase "prophetic minority." Coined by the journalist Jack Newfield, it neatly described the radicals of the '60s--the early edge who fought the first skirmishes on civil rights, protecting the environment, and other causes that eventually tumbled into the mainstream.

For me, though, there is another important and immediate application of this idea. I see a phalanx of consumers--millions, actually--who constitute another kind of prophetic minority. They are the vocal loudmouths who were bitching about the nutritional bankruptcy of McDonald's fast food years ago. They're the ones who first took on Nike for their child-labor issues, who championed open source software at the expense of Microsoft, and who think the rise of SUVs is an eco- and foreign policy disaster in fifth gear.

It seems pretty obvious that companies ignore the protestations of today's prophetic minorities at their own risk. They are the canaries in the cage of the consumer culture. Still, the denial continues. It's easy to dismiss these activist consumers as troublemakers--cranks and crackpots who have always been around, and will never rise to the level of a real business issue. In an age where preferences set over years are increasingly fragile and volatile, however, I believe that companies can no longer avoid the unpleasantness of unmediated voices.

The good news for entrepreneurs is that it is not hard to engage the prophetic minority. Companies must take the difficult step of eschewing the anodyne of traditional research--tracking studies and attitude and usage assessment--the entire armamentarium of probes. These measures are too polite, too distant from the roiling consumer psyche to be of much use anymore.

Instead, businesses should gather and study the authentic scribblings of the prophetic minority, which are everywhere--a kind of corporate graffiti. One obvious place to look for them is in the e-mail and phone messages received on a daily basis by your customer service reps. But the best place to find them is where you can find just about anything else these days: on the Internet.