John Hockenberry, a former NBC Dateline correspondent, writes a fascinating article in the January/February 2008 issue of MIT's Technology Review in which he talks about how the US news media actively chooses to go with emotion-centred news stories (that appeal to as many people as possible) as opposed to more relevant, hard-hitting, and (dare I say) real news stories.
Networks are built on the assumption that audience size is what matters most. Content is secondary; it exists to attract passive viewers who will sit still for advertisements. For a while, that assumption served the industry well. But the TV news business has been blind to the revolution that made the viewer blink: the digital organization of communities that are anything but passive. Traditional market-driven media always attempt to treat devices, audiences, and content as bulk commodities, while users instead view all three as ways of creating and maintaining smaller-scale communities. As users acquire the means of producing and distributing content, the authority and profit potential of large traditional networks are directly challenged.
It's a long article, though, so if you want a quicker version, read what Jacqui Cheng has to say about it over at Ars Technica. Both are great to read, by the way.