A Good Summary of Internet Trolling, Propaganda and Manipulation Techniques

"They overwhelm comment sections of media to render meaningful dialogue impossible.

The effect created by such Internet trolls is not very big, but they manage to make certain forums meaningless because people stop commenting on the articles when these trolls sit there and constantly create an aggressive, hostile atmosphere toward those whom they don’t like.

The trolls react to certain news with torrents of mud and abuse. This makes it meaningless for a reasonable person to comment on anything there.”

[link to en.wikipedia.org (secure)]