Meta-Blogging: Commenting

To revisit my question in class, I'm still wondering whether there is a way to foster more of a discussion, via comments, on a blog like this. I agree totally with KSalib's point that commenting can take a lot of time. I'm certainly the sort of irresponsible student who will spend an hour constructing a comment on a post rather than doing my homework. However, even in the Halcyon days of weeks 1-3 there were not a lot of comments. It seems like their rate has been more or less steady over the quarter.

My first thought was that people were uncomfortable publicly disagreeing with fellow students and also unwilling to get into a protracted discussion that might take up a lot of time. Another reason that seems plausible to me is that the odd disjunct between the informal nature of blogging and the formal nature of classwork made it hard to gauge how to approach comments. As somebody else pointed out, it feels a bit wrong to just comment "oh, that was cool, good post." However, I don't necessarily think that such comments should be discouraged. I did wonder whether the fact that post authors often did not return to reply to comments was partially a cause. However, even on threads where authors did respond, the conversations never went far. The final issue I thought of was that people weren't sure about the blogging medium itself. This is a two-fold question, in my mind. First, since we are pioneering the idea of a course blog (certainly I've never participated in one), were we just unsure what was appropriate? Second, have some (or many) students just never used a blog, either as a blogger or a reader?

I'd be interested to know whether any of you have suggestions for how to inspire comments on a course blog. The easy answer is of course for the professor to mandate comments, but that seems like it would lead to forced comments rather than a useful discussion. Another less formal way would be to mention that they would factor into the participation or blog grade, or serve as extra credit for one of those categories. This might be the most straightforward method to inspire good comments, but I wonder if there is a more organic way.

PS to non-class member lurkers: Commenting was not restricted to class members but nobody outside of the class commented (aside from one of my comments which another person [TE] contributed to). I know that one person tried but couldn't get blogger to take his post, a bug that seems to occasionally pop up on blogger/google platforms. But I'm wondering, was there something stopping you from commenting, or did you just never feel the urge?