Keith Olbermann is a guest on the Late Show with David Letterman tonight, and part of their taped conversation has already been uploaded onto YouTube by the show. In it, Olbermann and Letterman discuss the the dumbass Twitter fight he got into with Penn State fans and students that led ESPN to suspend him from his show for four days. Olbermann says that he didn't read the link included in the tweet somebody directed at him, and therefore thought that they were attacking (instead of supporting) charitable efforts to fight pediatric cancer. As he put it, "I just went back at somebody, and they weren't even throwing punches."