I can see many applications for blogs in the classroom. Anytime the teacher posts a new item the students could comment according to teacher given guidelines. Say the teacher posts a short video clip. Students could simply comment with their reactions. Did they like it? Why or why not? In foreign language classes the teacher could have questions about the short clip that the students would need to answer. For a classroom blog the students could be authors and post writing samples or their own videos or audio recordings to the blog. The possibilities are endless! Here’s some good information on blogging and setting up an online hub.
If you haven’t check it out already you really should go to freetech4teachers it’s a great site for getting ideas on tech integration and most are free to use. One of my favorites!