March 21 [16:00 EST] -- Folk songwriter/rock singer Ani DiFranco hauled two of her like-minded colleagues onto stage at her New York City show Wednesday night. She didn't introduce them until after they performed their cover of Prince's "When Doves Cry," but the enthusiastic response from the girl-power crowd made it obvious that they didn't really need to be introduced to Emily Saliers and Amy Ray of the Indigo Girls.

The crowd at the Roseland Ballroom immediately erupted as the Indigo Girls joined the blue-haired Difranco for her encore. And why not sing along with the well-known Prince hit? The crowd already seemed to know all the words to every song DiFranco played during the hour-and-a-half show.

DiFranco may have released every one of her albums on her own independent label, Righteous Babe Records. She may rely more on word of mouth than on radio airplay. But her grass-roots approach works. Throughout the show, the audience participation paused only as she introduced a brand new song, during which the entire place fell silent as the devoted fans listened intently.