Another thing that I would like to share is a WordPress plugin JuLiA which is in beta though but is great in comment moderation tasks.
JuLiA stands for Just a Linguistic Algorithm. This plugin checks your comments against the JuLiA web service, which supplies an abusiveness score for each comment. Based on this score, comments are auto-published, auto-deleted, or marked for review. Over time, scores are aggregated by commenter in order to generate abusiveness rankings and other statistics.

Great. Isn't it? I sense a good scope of its development. My wishes to the author!