Here is an excellent chart that graphs the web of unseen influence in media ownership:

The greatest threat to the future of the USA does not come from terrorists, or global warming, or electronic voting machines, or globalization, or
the national debt, or nuclear proliferation, or the health care crisis, or the collapse of vital infrastructure.
The greatest threat to the future of the USA comes from our own mainstream news media.
No, I am not indulging in hyperbole.
The US mainstream news media, monopolized as it is by corporate interests, has failed to live up to its Constitutional obligations. It has been craven
and complicit in the purveying of denial and disinformation about global warming and flat-out lies about the war IN, OF, BY and FOR terror.
Indeed, in some ways, we do not have a news media controlled by government, we have a government controlled by the news media.
I call it the greatest threat because over the past few decades, lacking a mass news media that delivers nutrient-rich content, our citizenry has
become informationally malnourished; and consequently, our citizenry has lost the sharpness of mind and the strength of will to overcome all the other
threats mentioned (any one which could bring this nation to its knees).
If the US mainstream news media had lived up to its obligation to pursue the truth and deliver it, with continuity and astute aggregation, then Bush,
Cheney, Rice, Rumsfeld, Rove, Gonzalez, Libby would be struggling to defend themselves in court instead of negotiating book deals or building
libraries.