Justin Levine raises some very good points. I agree with just about every one of his arguments, but I do see value in blog comments in spite of the many drawbacks Justin describes.
A phone conversation is only heard by one person. Comments may be read by tens of thousands. Or by one, but there is no way a phone conversation can have the same reach. Comments allow a guy in pajamas to correct an error or make a point that would otherwise be left out of public discourse. I would not be writing this post if it were not for the pajamas effect.
The poor quality of debate in comments has often almost driven me to (temporarily) give them up. The constant pattern of make a statement, defend against the straw man, defend against the next straw man, and again, and again, until the “debate” ends with ad hominems is very frustrating. It sometimes requires more patience than I can muster. Be that as it may, half of the point in my mind is teaching people how to think through issues logically. For every brain-dead ideologue there are ten curious people who may learn reason. It can be worth the effort.
The monitoring of comments must be tiresome. Freedom draws abuse which runs the gamut from the profane to the off-point. But readers can tune out the trolls. Trolls are not persuasive. However, they can effectively shut down debate and thereby stifle the ideas they oppose. This is annoying, but over the long haul those ideas are still getting out.
Anonymity certainly can encourage abuse, but it can also lead to more openness. For all of their infuriating annoyances, blog comments on sites like Patterico’s are the only place I know where at least somewhat open minded conservatives and liberals share ideas. I know that my ideas have been influenced by the experience and my respect for the other point of view has often increased.
Ultimately, each format has advantages and disadvantages. I am glad to be able to use both, and I wouldn’t want Justin to change a style that works so well for him.