Probably the same thing that happened to Gallup after Moveon.org accused them of being biased toward Republicans. They moved hard left in order to show that they're "fair".
However Foxnews is built mainly on conservatives or conservatives leaning viewers and they shoud be afraid of us leaving them. On the other hand they think that conservatives has no where to go.
May be it is time for a smart businessman to have the Conservative network. It will be the most succeful news network of all times.