Khoi Vinh on the decline of comment quantity on his blog, speculating that commenting might be declining more generally on most non-huge blogs:
I think what’s really happening is a simple matter of divided attention: there are much more absorbing content experiences than independent blogs out there right now: not just Tumblr, but Twitter and Facebook and all sorts of social media, too, obviously, and they’re drawing the attention that the ‘old’ blogs once commanded. Moreover, these social networks allow people to talk directly to one another rather than in the more random method that commenting on a blog post allows; why wouldn’t you prefer to carry on a one-on-one conversation with a friend rather than hoping someone reads a comment you’ve added to a blog post, number 59 out of 159?
Comments have always been a dysfunctional medium. They solve a real problem: authors’ need for validation, criticism, and feedback. But they solve it in a way that discourages civility and following up, and encourages hatred and spam.
To address the same problem that comments solve, I post links to my articles on Twitter, read my responses there, and react if necessary. This has most of the value of ideal comments, but with very few of the drawbacks.