Barack Inching Ahead -- in Media Mentions

While we all know the news from the polls is that Barack Obama is on a roll and has taken over the lead in the delegate count, a more subtle switch has also occurred since about Super Tuesday. Obama is leading over Hillary Clinton since then in the total number of media mentions (the individual occurrences of the person's name). Before Super Tuesday, Clinton was most always ahead of Obama.

So while the number of documents in which each gets mentioned is about the same (essentially, you can't write about one without at least mentioning the other), the number of mentions within those documents has switched.

Have the members of the press shifted their collective mindset? Are they subconsciously jumping on the Barack bandwagon?