The silly people over at the New Republic seem to be obsessed with the use of the term "mainstream media." I think it is, in part, due to the fact that as is often the case the media tends to internalize right wing critiques and then get confused by left wing critiques. It's actually a term I try not to use all that much, though for a lack of a better term I inevitably do use it, and I think I've thus far managed to avoid using the conservatarian blogger term "MSM." I don't consider the term to be in itself an insult, but simply a general category (which may at times be deserving of insult). I don't think bloggers are the mainstream media's "nemesis" and I don't think we're revolutionizing reporting. I don't generally confuse "linking" with "reporting." I don't generally confuse punditry with reporting, opinion with fact, and have never claimed to be a reporter, even if at times I report stuff. In other words, I'm not a lunatic right wing blogger. If we could settle on a definition of "journalist" I could answer the question of whether I consider myself to be one, though in any case though I do perform occasional acts of journalism I doubt I would generally describe myself as such.
So, what do I mean when I write "mainstream media?" Basically I'm referring to the larger supposedly non-ideological print outlets (papers like the Times and the Post, magazines like Time and Newsweek), National Public Radio's news/talk programs, PBS's Newshour, CNN, MSNBC, the news programs of the 3 major national networks, etc... It's not a pejorative. It's just a classification.