After reading James Tomasino's article "Comments" and having some discussions on the issue via IRC, I began questioning whether or not comment systems such as Disqus and public feedback systems, in general, were beneficial.
When you read something and want to interact with it, what drives you to do so? Do you want to show appreciation, agreement, disagreement, suggest corrections, or carry on a conversation? While comment threads, like any conversation, can get hijacked away from the intended discussion, it doesn't necessarily mean that having a public feedback option is not helpful for social systems, unless the feedback option's purpose is for harm instead of benefit.
Conversation hijacking will always be an issue, regardless of the platform. For example, I could have gone off-topic with how labs.tomasino.org's formerly used Disqus, but doing so isn't worth the time and effort of a blog post.
At the end of the day, if someone wants to contact the author for anything, I feel they should be able to use whatever suits them best. With multiple options existing, site admins have the choice to pick the methods they prefer most and let users decide which of the options they prefer as well.
My rambling aside: I think that Tomasinos right. If you want to comment on a post, feel free to see my contact page.