There are differences from teacher to teacher and from school to school, so it's hard to made broad generalizations. But one that I would make is that online classes have more busy work or assignments to help students learn the material since you don't have the lecture and discussion that a traditional class does. In one class that my wife is taking right now, she has something like 10-15 tasks to do each week. Those may be chapters to read, videos to watch, online study group meetings, assignments, discussion board posts and replies, quizzes, reviews, or exams.

One thing online classes still suck at is discussion. I have yet to see a class where the discussion board experience was valuable or beneficial or not forced.