Keith Olbermann seems to be amusing himself by answering his critics who, respectively, amuse themselves by sending Olbmermann nasty tweets. Here’s a typical response to a commenter who is dinging Countdown’s ratings:

@mike1962walsh 2,000,000 per night. How many you got?

Looking at the ratings for Monday, Olbermann had 1.7 million viewers — when you combine his 8 p.m and 10 p.m. numbers: close enough, I suppose. (Now, compare Olby with Bill O’Reilly: His 8 p.m. and 11 p.m. numbers add up to 5 million viewers.)

But once Lawrence O’Donnell takes over at 10 p.m., how many viewers will Olbermann lose? There’s also the impending entry into the 8 p.m. slot of the dynamic duo of Kathleen Parker and Client Number Nine. That, too, will cost Keith a few.