How do these courses work? Are they free? Are there limited places? I've signed up for one, but I've no idea what's going to happen. Has anyone done this before?
I'm currently doing Machine Learning by Prof. Ng. They are totally free. You'll watch videos of lectures (not lectures in a class, lectures are made specially for this). There are weekly quizzes based on the classes, and programming assignments. I don't think places are limited but, they don't allow people to sign up after the last date.
I think that you _can_ join ml-class and db-class right now (the currently on going set of courses). It's only ai-class that has closed enrollment.