There is a recent No Dumb Questions podcast that addresses this kind of thing. Destin Sandlin from Smarter Every Day goes a little bit into the multi-direction war being fought between social media companies, their legitimate user base, and malicious posting.
I think he misses some of the the top-down bias in those companies, but at the same time he brings up some very legitimate points that I had not considered.
Definite recommendation.
