Alan Jacobs writes in Books and Culture about his disillusionment with the blog form as a source for intellectual dialogue. He rightly suggests that the form that privileges new posts cuts off the potential for dialogue in comments – readers don’t check back for more discussion, and move on within a week.
Although this matches my experience, I think also that he overlooks the possibility of continued discussion between blogs. Of invoking (with links) old posts of the initial poster and of others within a blog community. And maybe this can only work within a small community, and not on popular blogs like daily kos where the regular commenters number more than a dozen. But I think Jacobs is a bit overly-dismissive. Or perhaps I am overly zealous about the possibility of blogging for intellectual growth.