The founders of Internet startup Airbnb were accustomed to rejection. Joe Gebbia, Brian Chesky and Nathan Blecharczyk peddled to venture capitalists their idea for using the Internet to help people rent out a room, or even a couch, to frugal travelers. All of the venture capitalists took a pass. But after receiving funding as well as mentoring from incubator Y Combinator in 2009, the startup exploded. Airbnb — the name was originally Airbed and Breakfast in a reference to the use of airbeds for guests — has listings in 16,000 cities around the world and has booked more than two million nights. What those early VCs missed was a burgeoning trend in what is now called “collaborative consumption.” At the core of this trend is the idea that technologies like the Internet and smartphones can help consumers monetize assets that they own — their home or car, for example — in ways that were previously difficult or downright impossible. “There are two forces converging,” says Wharton marketing professor David Bell .…