In his 2000th post at Simple Justice, Scott Greenfield expresses his frustration with moderating comment threads:

  [I]t's the one aspect of this Blawg that makes me think I should hang it up. It gets unbearably tedious after a while, and sometimes painful to watch a topic veer off onto a tangent because the one commenter didn't get it (while insisting, always, that he did). . . .
  The comments are often as more fun than the post itself. It pains me to acknowledge this, but it's true. I enjoy the comments most of the time, and that's why I engage commenters regularly. But I don't enjoy the emails I receive after I ban someone, or delete or edit a comment, accusing me of intellectual rape. I don't need this from people who have never contributed to the discussion here and whose thoughts are, in my view, less than worthy of much discussion. I will tolerate a lot more from people who I like and have been regular contributors, even when they get testy with me. I won't tolerate much from people I don't know or don't like. That's how things work in real life, and they are no different here.

  Blogs are still pretty new, so blog comment threads are, too. But I wonder if we're beginning to see a trend in comment sections already. As a blog becomes more popular, it becomes harder and more frustrating to moderate comment threads. There are just too many commenters out there to moderate each thread really effectively. Bloggers who try to moderate in good faith end up wasting great deal of time on a handful of individuals who feel that the world has wronged them somehow and that blog commenting is an effective form of revenge.

  For most high-traffic blogs, useful comment threads just aren't realistic. The two choices become an unmoderated thread or no comment thread at all. (A blog that has extremely high traffic numbers can try a Slashdot-like ranking system to try to bring attention to the best comments, but that requires enough traffic and the right reader culture to make it work.)

  If I'm right about all of this, readable and useful comment threads may end up largely only on blogs with traffic in the range of around 1,000 to 10,000 hits a day. Traffic below that usually won't generate enough commentary, and traffic above that usually won't allow effective moderation. My vague sense is that we're pretty much seeing this already, although I can't say that with certainty, as I only read a dozen or so blogs regularly. But I wonder if the realities of comment moderation will cement this trend over time.