Weblogs in Education and Training

On November 1, I'm to give a talk on weblogs at Metropolitan State University for a course on learning technologies. Unlike the weblogs and writing pedagogy talk, this one will have more of a focus on instructional design. The course centers on learning technologies in education and training that could take place in a corporate setting or a school. The instructor would like my talk to be a general introduction to weblogs and to cover ways they could be used for learning in each of these settings. She also wants me to offer tips on how to evaluate the effectiveness of weblogs. It's proving difficult! This discussion on Kairosnews is helping, and I want to do something with weblogs and WebQuests. In addition, I think Michael Angeles' work could be helpful. Do any of you have suggestions? I'd be grateful for them, as I'm somewhat out of my element here.