Diners take part in the Herbal Remedy Picnic event, a meal arranged through food sharing site Feastly, in Washington, D.C. Jeff Wilkes hide caption

itoggle caption Jeff Wilkes

Napster founder Shawn Fanning in February 2001, after a ruling that the free Internet-based service must stop allowing copyrighted material to be shared. Paul Sakuma/AP hide caption

itoggle caption Paul Sakuma/AP

Renting out your couches — or your entire place — is powered by San Francisco–based Airbnb, which has now connected more than half a million willing hosts and travelers in more than 34,000 cities. iStockphoto.com hide caption

itoggle caption iStockphoto.com