They are central disciplines of computer science, but they are not central in mind share; basically I'm seeing all of these articles on AI and ML (DeepMind, Comma.ai, tutorials on Deep Learning and Neural Networks), but not as much on things like networking, databases, and HCI. It would be nice to explore successful companies whose central focus is on one of those other disciplines.

I figured he was trying to find out real-world problems that actually demand the use of "cutting-edge" tech and practices.