Satire is an art form, and it isn't an easy one. Some publications get it, most don't.

The Onion attacks poorly written journalism and overblown headlines (usually by making really mundane ones), and their Onion News Network tv show assaults the 24 hour news channel format, with less focus on the content. Both work, but both also jab at separate things. They're successful because they play both mediums completely straight, and don't push things too far so as to make it obvious to the unsuspecting.

It's a very fine line, and a lot of places try too hard to be funny.