I'm taking the ML class and Dr. Ng occasionally mentions in the videos how he talks to Silicon Valley start-ups to helped them implement algorithms. What if the future professor not only make his money from teaching at a university but by consulting with businesses? She would just be using her expertise to teach in a different area. There's often a disconnect between academia and business that doesn't make a lot of sense.

+1 to what everyone else is saying in this thread about the Stanford classes, I'm loving the ML one so far.