Harrison Tang cares about his privacy and takes elaborate steps to protect it. Your privacy is another matter. Tang, 27, is cofounder of a “people search” website called Spokeo, which serves up extraordinarily detailed profiles of pretty much everyone — including you — gleaned from online directories, databases and social networks. The site began as a lark in a Stanford University dorm room but really took off when the improved version was launched in March after a move to Southern California. Suddenly the number of daily searches topped 1 million. About 100,000 people signed up for full access to Spokeo's...