Maybe you've noticed them in some of Sen. Barack Obama's recent television ads, the small print footnotes at the bottom of the screen as the narrator attacks Sen. John McCain. They cite newspaper articles, editorials, think tank reports and congressional votes. The print is so small and flashes so quickly, you'd have to freeze the frame to really read them. But the message behind these barely noticeably source citations is important. They are intended to add credibility and weight to the accusations being made. In Obama's case, the source citations are intended to back up the accusations, said Kathleen Hall...