Regular readers of this forum will know that I'm big believer in the efficacy of blogs as a learning tool; however, I also know that most likely says more about me and how I like to learn as it does about the medium itself.
I think it's imperative that blogs be "ground up" as opposed to something that's directed "from the top" (i.e., by a teacher, or as a course assignment). That's not to say that there's anything wrong with having blogging as part of a course (after all, weekly blog entries are part of my "current" course); however, I think the point is missed unless learners/students "get it" vis a vis blogs.
I've always enjoyed writing and that, I think, is part of the reason for the longevity (nearly three years) of this blog; however, as Downes indicates, blogging is more about reading than writing (see below).
While this forum has been at times more personal and professional than academic, it really does provide an excellent interface for reflection as well as a great spot for posting links and rants ;-)
Indeed, being able to revisit posts from years ago can be very informative (as well as humbling) in terms of how "learning" has served to better inform, or change entirely, one's views.
As Downes says in his article, "the jury is still out" on blogs, but he makes the point that blogs are more about "reading" than "writing." Furthermore, it's about:
reading what is of interest to you: your culture, your community, your ideas. And it is about engaging with the content and with the authors of what you have read -- reflecting, criticizing, questioning, reaching