If you're asking about FB, Twitter, and the like, I think they are all very bad for society, as they let each individual live in an imaginary bubble, "surrounded" by those who are like-minded, for the most part, and serve to puff up an individual's self-image to the point of a realty disconnect. Also, the lunatic fringe find that they are not alone in their insanity, and that gives them the "courage" to commit atrocities that we read about far too frequently, these days.