I believe that, whether by plan or more likely accident, the fireworks at MSNBC were a test case for the Obama fans in media. They saw the rampant partisanship going on at MSNBC resulted in NO negative fallout.
Also, Lou Dobbs has shown that one can easily go from objective reporter (which he was) to fiery op-ed vocalist, which is what all reporters actually want to be--they don't trust you, the silly uninformed ones, to GET the point of a story, they want to actually tell you what to think of what they're reporting.
So the success of OR, Dobbs and MSNBC--and the death of Tim Russert, in retrospect the one "balanced" member of the media--and the complete lack of criticism by those the media professionals respect--namely, each other--have given the liberal reporters the go-ahead to just go on and be biased. With the exception of a single piece in National Journal, I've not seen ANY self-criticism by the media. And that's the key--the media realized they were the only ones who'd be able to legitimize such criticism, so why not just DO it? They ALL think they're Tim Russert, they ALL think they're "unbiased" and just "telling the truth", and why deal with the frustrations of telling "the truth" and STILL having those morons (i.e. anyone not in the media, anyone who doesn't subscribe to the NYT) vote for THAT IDIOT BUSH NOT ONCE BUT TWICE??????
People get into journalism to make a difference in the world. But now that we all have access to all kinds of journalism, as opposed to just three liberal networks and the local papers, more and more opinions are available to us, more and more points of view that aren't from ABC/CBS/NBC. So they have to live in the new world, and the way to do that isn't just to create news stories that merely lead us to their own pre-ordained conclusions--they're just going to TELL us exactly how and what to think.
But we've had these hacks for a long time. Do you remember the hit job Larry King did on Bush one the Friday before the election in 1992? That jackass special prosecutor indicted Caspar Weinberger over Iran-Contra. King was attacking Bush in a lion's den of Republicans, and his eyes were bulging and he was sweating the whole time. But that scandal was a dirty trick, and went away right after the election was over and Bill and Hill won.
In 2000, a low level Gore operative in Maine launched the Bush DUI story. Rather and company got nailed by this board or Kerry might be running for re-election.
The rules changed in 1992, after a pretty good dry run and Quayle hunt in 1988. The media has always been deranged liberals, but there were lines they wouldn't cross before. Like you said, that's all out the door now.