They don't need phone numbers. If the code is running inside an app, it can snap location data and send it to a server. Along with that, they pull in whatever o

They don't need phone numbers. If the code is running inside an app, it can snap location data and send it to a server. Along with that, they pull in whatever other data they can link. This includes things like what model device, current battery level, home zip code, Facebook id, etc. With these data columns, you can match users pretty easily.