Why are some products and ideas talked about more than others? Why do some articles make the most emailed list? Why do some YouTube videos go viral? Word-of-mouth. Whether through face-to-face conversations, emails from friends, or online product reviews, the information and opinions we get from others have a strong impact on our own behaviour. Indeed, word-of-mouth generates more than two times the sales of paid advertising and is the primary factor behind 20-50% of all purchasing decisions.It is between 8.5 and 30 times more effective than traditional media.But want to know the best thing about word-of-mouth? It's available to everyone.Whether you're a Fortune 500 company trying to increase sales, a corner restaurant trying to raise awareness, a non-profit trying to fight obesity, or a newbie politician running for city council, word-of-mouth can help you succeed. And you don't have to have millions of dollars to spend on an advertising budget. You just have to get people to talk.The challenge, though, is how to do that. This book will show you how.

Jonah Berger is the James G. Campbell Jr. Assistant Professor of Marketing at the Wharton School at the University of Pennsylvania. He studies social influence and social epidemics, or how products, ideas, and behaviours catch on and become popular. This book is based on a popular, award-winning course Berger teaches at Wharton to undergraduates, MBAs and Executives. His research has been published in top-tier academic journals in psychology, economics, marketing and management, and popular accounts of his work have appeared in the New York Times, Wall Street Journal, NPR, Science, Harvard Business Review, Sloan Management Review, Wired, Business Week, The Atlantic, and The Economist. His research has been featured in the New York Times Magazine's Year in Ideas. Berger has been recognized with a number of awards for both scholarship and teaching, including the Iron Professor Teaching Award and the MBA Curricular Innovation Award from the Wharton School and best paper honourable mention from the Journal of Consumer Research. The Marketing Science Institute named him one of the top young scholars in the field.