Didi Chuxing, the president of Chinese ride-hailing giant Didi, and her father, Lenovo’s founder, have withdrawn from public view on China’s primary social media site, becoming the latest Chinese tech titans to do so. During the just-ended Labour Day holiday, Didi’s Jean Liu and her father, Liu Chuanzhi, both turned on a feature on China’s Weibo platform that hides all prior posts. Neither had made a post in the previous six months. The senior Liu, who has 880,000 followers, and his daughter, who has 10 million, did not disclose any reasons for turning private, but their decision was questioned by...