Here is a brief excerpt from an article by Dan and Chip Heath, featured in an issue of Fast Company a few years ago. As you’ll see, it has timeless relevance. To read the complete article, please click here.

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The police have issued this warning: “If you are driving after dark and see an oncoming car with no headlights on, DO NOT FLASH YOUR LIGHTS AT THEM!” Why? Because the no-headlights car is being driven by a gang member, and as part of an initiation rite, the first person who flashes him will be hunted down and killed. (But at least the gang member will turn his lights on afterward.)

You’ve almost certainly heard that famous urban legend, and most likely, you heard it from someone who swore that it was real. (It’s not. See snopes.com.) This idea is sticky — it’s memorable and may change the way you behave — but it’s also viral. People love to retell it. (Many sticky ideas aren’t viral. Your physics teacher may have come up with a mind-blowing demo for Bernoulli’s principle, but chances are you didn’t chat it up.)

Viral marketing has become a hip, low-cost way to reach a lot of people very quickly — with little effort. But as marketers, including giants such as Anheuser-Busch, Coca-Cola, and Procter & Gamble, slash ad budgets, “viral” needs to mean more than “free” and “fueled by prayer.” Making an idea contagious isn’t a mysterious marketing art. It boils down to a couple of simple rules.

Why is the gang-initiation tale so irresistible to pass on? Notice a few things about the idea. It’s emotional — in fact, if you believe it, it’s terrifying. The French psychologist Bernard Rimé has found that people almost compulsively share emotional experiences (both positive and negative), and the more intense the emotion, the more likely they are to talk about it.

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To read the complete article, please click here.

Dan Heath is a consultant at Duke Corporate Education, one of the world’s top providers of executive education. Prior to joining Duke, he was a researcher at Harvard Business School, writing 10 cases on entrepreneurship that are used in business school programmes. Heath is also the co-founder of Thinkwell, a publishing company dedicated to creating high-quality, multimedia university textbooks. Dan has an MBA from Harvard Business School. He lives in Raleigh, North Carolina.

Chip Heath is a Professor of Organizational Behavior in the Graduate School of Business at Stanford University. His research examines why certain ideas – ranging from urban legends to folk medical cures, from Chicken Soup for the Soul stories to business strategy myths – survive and prosper in the social marketplace of ideas. His research has appeared in a variety of academic journals, and popular accounts of his research have appeared in Scientific American, the Financial Times, the Washington Post, BusinessWeek, Psychology Today, and Vanity Fair. He lives in Los Gatos, California.

They are the co-authors of Made to Stick, Switch, and the forthcoming Decisive.