After two years of relentlessly bad ratings news, Katie Couric finally has something she can smile about. . . That makes four straight weeks where her audience was bigger than at the same point last year, according to Nielsen Media Research. The improvement could be a result of the positive feedback Couric received for her interview of GOP vice presidential candidate Sarah Palin during the presidential campaign. Palin fumbled on a question about what publications she read regularly, and the interview was a launching point for one of Tina Fey's "Saturday Night Live" spoofs.