As a student in one of the main universities in northern Italy, I can tell you the lessons are provided through the open source platform BigBlueButton. Student/teacher personal sessions although seem to rely primarily on skype.
I can't imagine how frustrating using that for lessons (so multiple connected parties) would be - it's hard enough to make it work with just two parties. Either the video works and no sound, or sound works but no video. Or just doesn't even connect.
Very unreliable from what I've seen.