Hello Tom, I agree with you in principle, we certainly do not wish for students' participation in class to be overlooked in any way. Especially for those with sparse participation. However, when you indicated "…make sure you respond…all comments," there maybe appropriate times for the instructor to "sit out" and be the guide on the side. Of course, your point about "students who only submit once" is an excellent recommendation. Definitely a providing a mini-dialogue to learners of that nature for encouragement and confirmation is a solid approach. Dr. S. David Vaillancourt