Two years ago, at the request of yours truly, the people at Nielsen crunched some numbers. They found that in times of major breaking news -- the examples used were the Columbine shooting, the Sept. 11 attacks, the commencement of the Iraq War, the Japanese tsunami and the death of Michael Jackson -- ratings for all three cable news outlets tend to rise. But, almost without exception, the most dramatic spikes on a percentage basis are enjoyed by CNN. The week of Sept. 11, its ratings rose by 800 percent. No other network came close.