Chris Bowers has a post about the netroots consensus generation machine. I think some people reading it will miss the point and decry the hegemony of the big bloggers or something so let me add my two cents to shift the emphasis of what he wrote slightly.
News, current events, whatever, is an ongoing story about the state of reality. It's an ongoing story with a cast of characters, a set of plotlines, a backstory. It's story told by thousands of different unreliable narrators, and every individual hears some combination of these narrators and then roughly synthethsizes it all into a basic narrative about what's going on. For a long time conservatives have had a very large and loud narrative generation machine, which has for its viewers and listeners been able create the narrative by emphasizing certain facts (true or not), by creating bad guys and good guy, by determining what the important stories of the day were, by inserting certain basic assumptions into the debate, etc. In other words, to write the story. And, this machine has been loud enough to have a big impact on how the less partisan media told their story, too.
On our side we had the never-was-all-that-liberal-and-certainly-haven't-been-for-some-time outlets like New York Times and NPR, where "balanced" reporting commentary is the norm. Whatever the merits/slant or lack of for NYT and NPR generally, the "two sides to every story" approach doesn't actually serve to generate a basic liberal narrative about events, a common thread which we can all follow.
Now with blogs and a bit more genuine liberal talk radio we finally have our own narrative generation machine, and people who follow them regularly are following a basic storyline. The point isn't that there's consensus on all issues all the time, but we're largely operating within the same basic story, our little model of reality.
...adding: The only other liberal consensus generating machine we had previously was The New Republic. Edited as it was by noted liberals Michael Kelly and Andrew Sullivan, and noted wanker Peter Beinart, it hasn't been very successful for obvious reasons.