According to BBC/Reuters/Media Center research, the most trusted media brand in the United States is Fox News, and the most trusted in Egypt is Al Jazeera.
This tells us something about "credibility" that I find troubling: A great many people aren't looking for fairness, or balance, or authoritative reporting, or accuracy, or the other values of professional journalism that some of us, at least, hold dear.
They're looking instead for affirmation. Something that blends happily with a pre-existing belief system. Something that substantiates prejudices.