The Daily Show bit here.
Okay, so I get that they both deal in lowest common denominator news and disaster coverage and, naturally, there's the usual cable news hackery.
In a realistic sense, though, I don't see how Chris Matthews is the liberal (?) Bill O'Reilly or how Olbermann is the liberal Hannity. Matthews is a fairly typical centrist-meets-opportunist who doesn't really push a liberal ideology. And Olbermann, while clearly amplified (and infinitely more thoughtful) in the context of his special comments, doesn't deal exclusively in the realm of opinion, as Hannity does exclusively.
And then there's the issue of false equivalency. This might sound hyper-partisan, but most liberal pundits (how many are there, really?) are more thoughtful, personally accountable, more factually accurate, and generally smarter than their conservative counterparts. For instance, I don't see Hannity delving into the subtleties of constitutional law.
So to imply the two networks are ideological mirror images, while funny on the surface, doesn't speak to any sort of larger truth. MSNBC's straight news coverage doesn't appear to spin left as FNC's news clearly spins right. And for the record, Scarborough is on for at least three hours a day while Keith and Rachel combined are only two hours.
Yeah, I know. I'm taking the bit too seriously.