Sharing is a diverse, prehistoric, and increasingly signi! cant contemporary consumer behavior, as suggested by a few examples:

In most foraging hunter-gatherer societies, everyone in the village of a successful hunter • is free to claim a piece of meat. In • Th e Republic, Plato proposed an ideal society in which private property has a limited role, and a culture of public sharing prevails. Napster was the ! rst successful large-scale system of ! le sharing in which users freely • shared music, ! lms, and digital copies of other documents. Car-sharing services like Zipcar work because they are more a ordable, environmentally • responsible, and convenient than private car ownership. # e Robin Hood $ our company encourages children, with the help of their parents, to • bake cookies and share them with neighbors. Hundreds of thousands of people contribute advice, facts, opinions, photos, videos, and • so" ware code online each day. Because of such information, as well as online support groups, it is possible for medical • patients to know more about their illnesses than their doctors do. Our public parks, libraries, roads, ! re departments, museums, and recreational facilities • are freely available for all.