As usual, the Huffandpuff Post and the author of this article get it wrong. Rush Limbaugh does not hold an FCC license. They can do absolutely nothing to him. Ms. Fluke can sue him for slander if she wants, but neither Limbaugh nor the individual stations that carry his show did anything illegal.
It is not a criminal act to call someone a slut, prostitute, or even the "N-word," nor are those words considered obscene. It's distasteful, those words are disgusting, and could get you in deep pucky in a civil court, but nobody is going to jail over it. Nor will any of his affiliates lose their broadcast license.