A century and a half before the social web, Danish philosopher Søren Kierkegaard (May 5, 1813–November 11, 1855) captures the psychology of online trolling and bullying perfectly in a diary entry from 1843:
There is a form of envy of which I frequently have seen examples, in which an individual tries to obtain something by bullying. If, for instance, I enter a place where many are gathered, it often happens that one or another right away takes up arms against me by beginning to laugh; presumably he feels that he is being a tool of public opinion. But lo and behold, if I then make a casual remark to him, that same person becomes infinitely pliable and obliging. Essentially it shows that he regards me as something great, maybe even greater than I am: but if he can’t be admitted as a participant in my greatness, at least he will laugh at me. But as soon as he becomes a participant, as it were, he brags about my greatness.
Read more here, then couple with a modern counterpart: Anne Lamott's ultimate manifesto for handling haters.