MSNBC doesn't label itself as a news show, and even admits to only having about 10% news, where Fox deliberately blurs the lines between what is news and what is political talk. Also in a study linked by our very own Vyxn, something like 40% of Fox viewers trust Fox to deliver them real news, where <10% of MSNBC viewers trust MSNBC to deliver them real news. Considering the amount of Fox News right wing rhetoric that is repeated on these forums, I'd say a lot of that 40% post here.
Also, I'd hardly call the actual "news" that Fox news posts as news to be anything worthy of even paying attention to, considering that what they deem to be news is reporting on trailer park disputes and various irrelevant American urban living stories.