Your apps know where you were and they’re not keeping it a secret

The millions of dots on the map trace highways, side streets and bike trails — each one following the path of a cellphone user. One path tracks someone from a home outside Newark to a nearby Planned Parenthood. 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 miles away, staying until late afternoon each school day. Only one person makes that trip: Lisa Magrin, a 46-year-old math teacher. Her smartphone goes with her.

An app on the device gathered her location information, which was then sold without her knowledge. It recorded her whereabouts as often as every two seconds, according to a database of more than a million phones in the New York area. While Magrin’s identity was not disclosed in those records, The Times was able to easily connect her to that dot. The app followed her hiking with her dog and staying at her ex-boyfriend’s home, information she found disturbing.

“It’s the thought of people finding out those intimate details that you don’t want people to know,” said Magrin. Like many consumers, Magrin knew that apps could track people’s movements. But as smartphones have become ubiquitous and technology more accurate, an industry of snooping on people’s daily habits has spread and grown more intrusive. Lisa Magrin is the only person who travels regularly from her home to the school where she works. A visit to a doctor’s office is also included. The data is so specific that The Times could determine how long she was there.

In about four months’ of data reviewed by The Times, her location was recorded over 8,600 times — on average, once every 21 minutes.

At least 75 companies receive anonymous, precise location data from apps whose users enable location services to get local news and weather or other information, The Times found.

Several of those businesses claim to track up to 200 million mobile devices in the US. The database reviewed by The Times — a sample of information gathered in 2017 and held by one company — reveals people’s travels in startling detail, accurate to within a few yards and in some cases updated more than 14,000 times a day.

These companies sell, use or analyse the data to cater to advertisers, retail outlets and even hedge funds seeking insights into consumer behaviour.