Keith Olbermann unexpectedly announced he was leaving MSNBC last night. Olbermann is MSNBC's highest-rated anchor, and the main reason the network now stands as the left-leaning alternative to Fox News. So why'd he quit? Or was he fired?

Early reports make it unclear who dumped whom, but Olbermann was probably forced out, two years before the end of the four-year, $30 million contract he signed in 2008. 'Cause you don't see a happily resigning anchor sign off abruptly one night with grandiose allusions to the final scene of Network. Ever since Olbermann was suspended briefly in November for donating to the Democratic politicians he openly supported every day to his millions of Countdown viewers, things have been not very good between him and his corporate overlords at NBC Universal. Olbermann was unapologetic on air, and who knows what went on behind the scenes.

Conspiracy theories suggest that Comcast, which is about to take over NBC Universal, might have forced Olbermann out. Let's not flatter Olbermann (he can do that well enough himself): Comcast execs didn't sit in a dim room with a big marker and draw an "x" through Olbermann's name. But certainly the departure of Olbermann's longtime protector at NBC, Jeff Zucker, has something to do with the timing of the move.

Of course, there's a third possible reason that we just made up: Maybe Keith Olbermann is replacing Regis on Live with Regis & Kelly after he retires? The show's name will be changed to Worst Breakfast In the World.

How will this impact MSNBC's future? Who knows! Sure, they lost their highest-rated anchor—but they're bring on some guy named Cenk Uygur to fill in at 6 pm. Apparently he runs a very popular video podcast on YouTube.