Book excerpt: The Wall Street Journal and BusinessWeek bestseller-fully revised and updated The old cliché is that smart companies underpromise and overdeliver. But in today's crowded market, underpromising is a ticket to oblivion. Companies like American Girl, Best Buy, and Apple came out of nowhere to dominate their markets. How did they scoop their bigger and wealthier competition? It wasn't through a fat marketing budget. It was because they made, and kept, dangerously ambitious promises. In fact, they overpromised to lure customers in-and then overdelivered to keep them. Rick Barrera shows how to make sure that every point of contact between your company and its customers is well executed and fulfills an over-the-top brand promise, to drive word of mouth and rapid growth.