Contagious: Why Things Catch On

by Jonah Berger

People share more than 16,000 words per day and every hour there are more than 100 million conversations about brands.

Give people a way to make themselves look good while promoting their products and ideas along the way. There are three ways to do that: (1) find inner remarkability; (2) leverage game mechanics; and (3) make people feel like insiders.

Emotions drive people to action. They make us laugh, shout, and cry, and they make us talk, share, and buy.