Jeremy Hiebert makes an interesting comparison between blogs and LMS in higher education:
In spirit, blogs are the opposite of a Learning Management System like WebCT. If you lock personal publishing away inside an LMS, it’s the equivalent of yet another crappy discussion board in a course. Blogs work because people are engaged in their own interests and can find their network from the entire world. An LMS constrains the topic, assignments and partipants, closing off any potential for authentic outside interaction and personal engagement.
Could not have said it better myself – it’s about learner control.