A Pew Research report (behind a firewall here, but summarized below)
Pew judged the levels of knowledgeability (correct answers) among those surveyed and found that those who scored the highest were regular watchers of Comedy Central’s The Daily Show and Colbert Report. They tied with regular readers of major newspapers in the top spot — with 54% of them getting 2 out of 3 questions correct. Watchers of the Lehrer News Hour on PBS followed just behind.
Virtually bringing up the rear were regular watchers of Fox News. Only 1 in 3 could answer 2 out of 3 questions correctly. Fox topped only network morning show viewers.
Told that Shia was one group of Muslims struggling in Iraq, only 32% of the total sample could name "Sunni" as the other key group.
Fox is almost always covering some "tabloidish" story (I am starting to include these real0life "cases" that news seems to want to follow nowadays as "tabloid", even though they are attempting to "cover" some actual, often tragic events and crimes. But I wonder why they are considered news to anyone outside of the immediately affected communities. I have NO interest in following the details of these cases. And Fox leads the way on these. Given the above stats on actual news knowledge, this fits the Fox mold.