Riverdale is quickly proving itself to be a smart soap opera, as much about the unfinished business of adults as the teens solving an unnerving murder mystery. The Greg Berlanti?produced soap show 2.3 million same-day viewers on Thursday night. It notched a 0.8 rating in adults under age 50, which more than doubled its May finale tune-in. That number also jumped 67 percent above its heavily promoted January series premiere.