Two-time defending Formula One World Champion Sebastian Vettel appeared on CBS' The Late Show with David Letterman Monday night as part of an F1 media blitz.
These days, there are some serious battle lines drawn around which late-night host you prefer. With the embattled Conan O'Brien taking to the airwaves for the first time since being ousted from NBC, we can all but guarantee another outpouring of down-with-Leno sentiment. But who are the rank and file that make up the heart of each suit's fan base? Who is it exactly that watches Letterman, and how do they differ from Stewart's army of fans?