Piazza (forums) and office hours (bluejeans--think youtube livestreams but on a proprietary platform.

For me, this semester, I finished a group project where we coordinated over slack/google hangouts. After that project, I didn't have anything left to finish the semester. I felt like I was done because the reinforcement loops I get from work (virtual back-clapping) were done and I had a hard time separating that from the "here's the next task. Also no one is talking to you about what needs to be done."

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.

Interesting. I would imagine that doesn't make you feel like your classmates are your peers, and it would be hard to make friends with them. Friendship or at least friendliness goes a long way towards motivating people to learn stuff. Moreover, networking is an important reason for going to grad school, but it seems like the school is not encouraging this.