Social Networking Sites are legitimate communication tools, and can be a fast way to get all kinds of information, from people you already know as well as the rest of the world. And they have proved useful in disseminating health information where timeliness is key: disasters, flu outbreaks, etc.
But is there no quick way to evaluate the information you find on Social Networking Sites! Anyone can register any identity on any social networking site. Make sure to pay close attention to where the information comes from, and to back up what you hear with information from authoritative sources and your health provider.