Facebook. Amazon. Apple. Not too long ago, these were the companies upending the status quo--unleashing provocative business models that changed our daily lives even as they transformed entire industries. (See: bookstores, record labels.)
Now it's their turn to face the newbies. Buoyed by rocketing investor enthusiasm--venture-capital funding hit $28.4 billion in the U.S. last year, up 22% from 2010--the next class of start-ups aims to disrupt the disrupters. "Are we worried about iTunes? Of course," says Daniel Ek, CEO of Spotify, a much hyped app that offers streams of songs legally and free. "But our goal is to be the best...