I would used 'weblog' for classroom discussion. I know there some student who talk a lot and there are some who are very quiet. When you have discussion you do not have to talk, at the least , you have to no how to write. Even if you are loud or quiet, writing is universal to both groups. Knowing this siutuation, I would make the students feel comfortable on both sides. Also, you will get interesting views from student that in a normal setting will probably keep the information to themselves. Hopefully, the students who does all the talking can learn from students that on the past would never voice there opinion.