Your post reminds me of something Harold Jarche wrote:
Books gave us the illusion that knowledge was stable. It never was.
Books, and by extension linear text, are not organised like we think. We need tools that allow us to interact online like we think. I love blogs for teaching, the to and fro through comments is great. However, it doesn’t quite catch the “conversation that develops BETWEEN people”. A blog like tool that allowed comments, or comment boxes within the post would get closer to allowing people to converse. Blog posts still present ideas in a linear fashion, to which we respond through comments, but I often want to comment on a part of a post, not on the whole thing. That’s closer to a conversation than commenting at the end.