There’s too much information out there for most people to pay attention to, let alone figure out whether they believe it or not. Hence, most people rely on other institutions such as media organizations to tell them which information is worth caring about. Not only do people not pay much attention to information until it gets the stamp of approval from some authoritative institution, but this information is transformed, because everybody knows that everybody else is paying attention to it. It stops being mere information, and becomes knowledge — generally accepted facts that people use to build their understanding of what everybody knows about politics.
via Why Glenn Greenwald’s new media venture is a big deal.