I think the comments section is the most undervalued part of a niche website. If sites are turning off their comment because of spam/moderation fatigue, it tells me there's a great opportunity for developers and makers to create better solutions. I, for one, would love to see a comment moderation service that is part-human powered to deal with the comments that pass through traditional anti-spam solutions. I find it incredible & encouraging that high traffic sites such as reddit/ycombinator can manage the insane amounts of spam they get without readers barely noticing a problem exists.

I concur with Otto and others regarding the Copyblogger example, they just made a calculated decision because sales is their only concern and that's fine, but the trade off is clear too: less value put on community, lower quality content, less engagement, less value rendered to newcomers. Conversations on social media are fleeting and typically forgotten in days, it's a bad proxy for a valuable comment thread on a blog.