As you may have heard once or twice before, it’s a marathon, not a sprint (unless, of course, you’re talking about a sprint, then it’s a sprint, not a marathon). But we digress. Mark Rosenthal, CEO of Current TV, uses the sports metaphor to express his lack of concern over the second-week ratings drop for Keith Olbermann’s Countdown. The show saw its ratings shrink by nearly a third during the week of June 27, averaging 93,000 viewers in the key 25-54 demographic.