Only a year ago, the charts were dominated by stars who had come out of the old machine of radio and major-label promotion: Katy Perry, Rihanna, Adele, Maroon 5. This year’s biggest hits — “Call Me Maybe,” Gotye’s “Somebody That I Used to Know” and Fun.’s “We Are Young” — started in left field and were helped along by YouTube and Twitter before coming to the mainstream media.

via How ‘Call Me Maybe’ and Social Media Are Upending Music – NYTimes.com.