Oprah's departure presents problem for TV stations (AP)

In this image taken from video Friday, Nov. 20, 2009 and provided by Harpo Productions Inc., talk-show host Oprah Winfrey announces during a live broadcast of 'The Oprah Winfrey Show' in Chicago that her daytime television show, the foundation of a multibillion-dollar media empire, will end its run in 2011 after 25 seasons on the air. (AP Photo/Harpo Productions, Inc.)   MANDATORY  CREDIT,  NO SALESAP - For more than two decades, Oprah Winfrey has been the inspirational, change-your-life champion who reigned over daytime television much like Johnny Carson once ruled late night.