Exclusive: Steve Bannon knows how often you go to church

Steve Bannon and the conservative group CatholicVote used cell-phone location data for people who had been inside Roman Catholic churches ... target them with get-out-the-vote ads...

“geofencing” or “ring-fencing.”... data ... is anonymized. But ... potential to reveal personal information about individual phone users... virtual fence around a geographic location, allowing data brokers and digital marketing firms to either serve ads to people while they are inside the fence or capture their phones’ unique IDs for later use ... ads themselves appear in apps or on websites as the person uses their phone...

some smart phone’s apps collect location data ... Many ... app makers then monetize that data, selling it to brokers ... does not include the phone user’s name or phone number. But ... New York Times ... was able to identify individual users and track them to a Planned Parenthood clinic, a middle school, an emergency room, and to their homes and offices...