Charles Zhang, a physics PhD holder from the Massachusetts Institute of Technology (MIT) and founder of Sohu, isn't chasing startup buzz or venture capital funding these days – he's picking up chalk, and his lessons are going viral. From internet trailblazer to blackboard sensation, Zhang believes a true CEO must be a hands-on product manager and a big user. On the U.S. blocking international student visas, he's direct: "It's bad news for young people. The so-called geopolitics should be kind of discarded. We are all neighbors and we should be united."