Diakopolous, N. & Naaman, M. (2011). Towards quality discourse in online news comments. Proceedings of the ACM 2011 Conference on Computer Supported Cooperarative Work. New York, NY.
A few notes/quotes from the article:
Early work in Computer-Mediated Communication (CMC) has documented how a lack of status cues and social context can introduce unwelcome low-quality contributions into online communication systems. Quality in this context refers to a degree of excellence in communicating knowledge or intelligence and normatively includes notions of accuracy, reliability, validity, currency, relevancy, comprehensiveness, and clarity [30, 31]. In the realm of online comments low-quality contributions might include “flaming” and more impulsive remarks  and are often implicated with anonymity, with less anonymity linked to higher quality comments.
crowd-based moderation has been effective, but this relies on two things: 1) pervasive and consistent online identities and 2) a homogenous attitude about what’s “good” and what’s “bad” amongst community members.