“Goofy, gentle, nimbly amateurish, jerking was little known outside certain precincts of this sprawling city [L.A.] until a year ago. But in the last nine months or so, jerking began an unexpected run as an Internet phenomenon.” The movement has a “rebellious disregard for the conventions of urban style and music (old school hip-hop artists are referred to as ‘baggy daddies’).”