Two top executives from public-relations and communications firm Burson-Marsteller will deliver a keynote presentation on digital communications in politics at BlogWorld & New Media Expo 2010 at the Mandalay Bay Convention Center in Las Vegas, joining the previously announced list of keynotes and speakers.

Burson-Marsteller CEO worldwide and Penn Schoen Berland CEO Mark Penn and worldwide vice chairman Karen Hughes will discuss results from a study of social-media use during the midterm-election races, analyzing how candidates used Facebook, Twitter, YouTube, and texting, and how they integrated their messages on other sites and social-media outlets. The keynote is scheduled for Friday, Oct. 15 at noon PT.

Penn has served as a senior adviser to Bill Gates, Steve Ballmer, Bill Ford, President Bill Clinton, Hillary Rodham Clinton, and U.K. Prime Minister Tony Blair. He is the author of best-selling book Microtrends, a regular guest on cable television, and a columnist for The Wall Street Journal.

Hughes served as under secretary of state for public diplomacy from August 2005-December 2007 and as counselor to President George W. Bush from 2001 to 2002, where advising the president on policy and communications.