I'm another dropout (loved some of the courses, especially the OS ones, have close-to-zero interest in machine learning, though, and that's maybe half of the cl

I'm another dropout (loved some of the courses, especially the OS ones, have close-to-zero interest in machine learning, though, and that's maybe half of the class offerings), but to answer your question, all the courses I was in had a "participation" component to the grade where you were expected to ask/answer questions on the online forum thing for your class. There were also optional office hours, as I recall. It was certainly nothing like just hanging out with colleagues in the cafe between classes, but for those (like me) who just can't go to a school like GT in-person, I'm glad the opportunity is available even though I'd say it's probably the hard-mode version of the program given the limited course catalog (not all courses are integrated into the program yet) and lack of in-person interaction.