Charles T. Downey is teaching a course on 20th Century Opera at Catholic University. Like me, he is having his students write in a class blog, though his students are decidedly older, the material is much more advanced, and the students (or Charles) picked a much more appropriate blog name than my students did (sigh). I've been staying out of the limelight with my students' blog, consigning myself to comments only. Charles has been posting extensively at his class blog, Opera in the 20th Century, but I think his purpose is different than mine. I'm trying to get some first-year students to regard writing as a process in developing critical thinking skills, and to take ownership for their ideas and writings. Charles is trying to get some graduate students to learn about contemporary opera, using the blog to supplement course discussions and materials. I imagine there are many possible uses for class blogs, which would certainly bode well for its future.
Many schools, including my own, use online discussion forums to augment classes. These forums are password protected, accessible only by the school or by the specific class. The benefit of class blogs is the public service it entails. Knowledge is being imparted by faculty and students not only to each other in a closed loop, but to the community at large. This is supposed to be the grand purpose of academia, one I find worthy of pursuit.