Granted, there are no papers to grade, and assignments aren’t free-form, but how does one professor handle so many students?
We had four teaching assistants, and my initial plan was that they would spend a lot of time on the discussion forum, answering questions. One night in the early days, I was on the forum at 2 a.m. when I saw a student ask a question, and I was typing my answer when I discovered that another student had typed an answer before I could. It was in the right direction, but not quite there, so I thought I could modify it, but then some other student jumped in with the right answer. It was fascinating to see how quickly students were helping each other. All we had to do was go in and say that it was a good answer. I actually instructed the T.A.’s not to answer so quickly, to let students work for an hour or two, and by and large they find the answers.