"One of Chris' biggest skills is emotional intelligence. He's just one of those rare people from an engineering background who excels at that," Facebook engineer Mark Slee said in a 2008 interview.
Cox ascribes Facebook's success to Marshall McLuhan's theory that all new technology, from roads to the printing press, was built to fulfill the basic human desire to connect with others. With Zuckerberg, Cox formulated "social design," the idea that people — who they are, what they do, what they care about, who their friends are — not software code, should shape new features and products.
"He has one of the best fundamental understandings of what Facebook is all about and what it is trying to do," Slee said. "He gets the super zoomed out picture."
Facebook has ruffled users by rolling out new designs and features. It has been frequently condemned for how it handles users' personal information, and even had to reach a 20-year privacy settlement with the Federal Trade Commission.