Why was Keith Olbermann's "Countdown" show abruptly terminated by MSNBC?

He was speaking truth to power, don't you know? He stood on the battlements, waving the bloody shirt and expecting us to follow his brave lead into the war against eeeeeevil conservatives and the "corporate media."

Or, he was a number one A-hole and nobody could stand him any longer:

Did Comcast-as many Countdown viewers seem to suspect-order Olbermann out? It appears that the end of the Olbermann era at MSNBC was not "ordered" by Comcast, nor was it a move to tone down the network's politics. Instead, sources inside the network say it came down to the more mundane world of office politics-Olbermann was a difficult employee, who clashed with bosses, colleagues and underlings alike, and with the Comcast-related departure of Jeff Zucker, and the rise of Maddow and O'Donnell, the landscape shifted, making an Olbermann exit suddenly seem well-timed.

The blunt, brief statement of Olbermann's final day, compared to the long, lush programming memo that makes no mention of Olbermann suggests that while the timing may not have been set, the foundation had been laid for today's move.

Update: Brian Stelter reports the following statement from Comcast:

"Comcast has not closed the transaction for NBCU and has no operational control at any of its properties including MSNBC. We pledged from the day the deal was announced that we would not interfere with NBCU's news operations. We have not & we will not."

If anything, Comcast is looking to go even more to the left on MSNBC in order to ape Fox News' success on the right. If they were interested in shutting up liberals, they would have demanded the firing of Maddow, Schultz, and O'Donnell as well.

Despite the conspiracy theories, the simple fact is Olbermann is a jerk - an egoist who believes himself the equal of Edward R. Murrow and whose shtick around the office just got old.

The left can't deal with that, though. They need martyrs. Unfortunately, Olbermann is only a martyr to mediocrity - a hateful, mendacious incoherent clown who outlasted his usefulness at MSNBC.