Jonah Berger is a professor of marketing at Wharton who spent years studying why things spread. His answer is not what most marketers expect. The quality of a product matters less than most people think. Advertising matters less. Price matters less. What matters most are the psychological motivations of the people who share. The first of Berger's six STEPPS principles is Social Currency. People share things that make them look good: intelligent, interesting, in-the-know, funny, generous, or informed. Before sharing anything, people, usually unconsciously, ask: what does sharing this say about me? Berger uses the example of a hidden bar in New York called Please Don't Tell. It operates behind a secret entrance through a working phone booth in a hot dog restaurant. The secrecy and exclusivity are not inconveniences; they are the product. Knowing about it and being able to get in is the social currency. People share it not because they want others to eat there, but because knowing about it makes them look like the kind of person who discovers cool things. For any piece of communication, content, or product to spread through social currency, it needs to make the sharer feel good about sharing it. The question to ask is: what does sharing this say about the person who shares it? If the answer is nothing interesting, the content will not spread.