This essay by Hilaire Belloc, The Free Press, describes accurately the nature of news sources, especially as concerns the "mainstream media vs. partisan media" side of things. It explains why someone who believes the news will inevitably get tricked someday.
The money quote (in which he compares the press with word-of-mouth):
The Press eliminates three-quarters of all by which opinion may be judged. And yet it presents the opinion with the more force. The idea is presented in a sort of impersonal manner that impresses with peculiar power because it bears a sort of detachment, as though it came from some authority too secure and superior to be questioned. It is suddenly communicated to thousands. It goes unchallenged, unless by some accident another controller of such machines will contradict it and can get his contradiction read by the same men as have read the first statement. [emphasis mine]