We all know ideas and information spread through word of mouth. But according to Berger, the key to making things really popular happens long before it's discussed at the water cooler or "liked" online. It starts with the message. Drawing on his groundbreaking research, he explains that there are six key steps that make products or ideas contagious. Those "STEPPS" -- Social Currency, Triggers, Emotion, Public, Practical Value, and Stories -- will help any product or idea spread like wildfire. Surprisingly, Berger also reveals just how little word of mouth is generated online versus elsewhere. Whether you're a public health official trying to get the word out, a small business owner trying to get your restaurant to catch on, or a manager at a big company trying to make your product popular, Berger's findings will help you craft products and messages that people will share.