The millions of dots on the map trace highways, side streets and bike trails — each one following the path of an anonymous cellphone user. One path tracks someone from a home outside Newark to a nearby Planned Parenthood, remaining there for more than an hour. Another represents a person who travels with the mayor of New York during the day and returns to Long Island at night. Yet another leaves a house in upstate New York at 7 am and travels to a middle school 14 miles away, staying until late afternoon each school day.
Only one person makes