During the time Fox has been on the air, it has transformed from a balanced network that gave equal time to conservative news and other viewpoints to one that is primarily just conservative. In the beginning it seemed more conservative than it was because the rest of the media tilted left. Thus just being in the center of the political spectrum put one to the right of the major media.
Partly because of Fox, however, the major media shifted more toward the middle than they used to be. This led Fox to move further to the right to maintain the space between itself and its competitors. Consequently, it has ceased being fair and balanced and is, essentially, the Republican news network. Academic studies show that those who watch Fox regularly become much more likely to vote Republican.