This article, "Some bloggers meet the bosses from big media," by Jay Rosen tells his account of a meeting held with three parties represented - bloggers, the big media and people involved in helping the transition between media in print and media on the web.
It offered a wide-range of perspectives on whether or not big media should be threatened by blogging or other forms of online media.
The main concern of big media is the cost to them to fully staff a newsroom.
All of the parties present at the meeting agreed that "the news business will eventually migrate to a new platform on the Net," but that this won't happen anytime soon. It was also agreed upon that big media doesn't know how to innovate and that they constantly lag behind the rest of the media and that a definite change initiative was needed.
But, big media doesn't think that blogs are necessarily credible due to the lack of standards, editing, etc. of traditional news.
I understand where big media is coming from when they say that blogs lack credibility due to lack of standards. The most common debates in the newsroom revolve around ethical discussions, policies, editing, accuracy, etc.
More of Jay Rosen's blog can be found at: http://journalism.nyu.edu/pubzone/weblogs/pressthink/