Since quite a few people have their own blogs in addition to graciously hanging out online with us here at Atheist Universe, I want to wholeheartedly and vehemently recommend THE BEST blog post on moderation comments. It is especially valid for science blogs, but not only for science blogs. The blog post is "Commenting threads: good, bad, or not at all" by Bora Zikvovic who is Scientific American's blog editor and organizer of the conference Science Online. It is lengthy but bookmark it, guys, the advice is invaluable. The short of it is that if one does not moderate comment threads swiftly, trolls take over (see the animated gif). But one of the most important reasons to moderate comments, especially in science, philosophy, or critical thinking blogs, in other words, blogs where the author aims to inform or educate readers, is that rude, uncivil comments in a thread result in immediate polarization, and instead of having a constructive, informative discussion, people become more polarized. This was demonstrated in an actual scientific experiment, soon to be published. The experimental setting was the following: a blog with fake, planted comments was posted on nanotechnology (a neutral subject that people are in general not a priori biased against or in favor of, such as evolution or climate change), and was given to two groups of people. The catch is that one group of people read the blog post with civil, polite comments, and the second group was given the exact same article but with uncivil, rude comments in the fake commenting thread. What happened is fascinating: the readers in the second group very quickly took one or the other side of the argument and became entrenched in that position, resulting in a misunderstanding or misreading of the original article. In other words, the readers became polarized. Bora thus argues that in a post about climate change, which is a phenomenon on which there is a vast scientific consensus, including about the effect human activities are having, there is no point in allowing "denialists" to post comments, because then there will be no real discussion in the thread, but essentially a useless flame war. The fact of anthropogenic climate change is not in question, what should be discussed are other very important subjects such as prediction, models, potential interventions, etc. The same goes for evolution: one should delete comments by creationist trolls, and instead discuss about the mechanisms, processes, different hypothesis as to how evolution occurs, etc. There is room for discussion, room for disagreement. In science there always is. But if you want to have a useful discussion, nasty or trolling comments have to go. I'm in full agreement with Bora on this matter. And not only in science. Many subjects come to mind, such as political ones, like health care, gun control, reproductive rights, etc.
He also gives other great advice, such as: engage your readers, visit your own blog often, allow people to disagree, actually, welcome vigorous disagreement as long as it remains civil. The tone of the comments affects your readers. Always take this into account.
Another great point he makes is about "free speech", or "freezepeach" like people on the internet jokingly say when trolls whine that they are being "censored". Commenting on a person's blog is a privilege. It's their blog, not yours. If your comment is deleted, your right to "freezepeach" was not violated, because you can go write your own blog. And work hard on getting it to be noticeable to the search engines. The blog's author is under no obligation to give you a platform with many readers, for your own rants.