Here's a good reason so much mainline journalism is junk - reporters can't do math:

"Math in newspapers isn’t so much doing arithmetic calculations, it is having a sense of numbers and proportions," said the Toronto Star science reporter, Peter Calamai. "It is having a detector that tells you, this just doesn’t add up. It is not that you have to be able to solve quadratic equations or do long division in your head or be able to work out square roots. It is that you need enough familiarity with things like relative size and proportion that you think, as you would if you were an expert in political science ‘Well that doesn’t make any sense.’ "

It boils down to this: "Numerate people, as a rule, do not choose to be journalists. If they like numbers, if they like analyzing data, they can make better money in a whole range of other careers than journalism," said Bruce Little, reporter for the Globe and Mail.

Instead, they enter other career fields, then some become bloggers. I wonder whether numeracy, or mathematical literacy, is one thing that draws more and more people to read and write blogs, and whether it's a reason so many mainline media feel threatened by blogs.