The millions of dots on the map trace highways, side streets and bike trails — each one following the path of an anonymous cellphone user. Another user leaves a house in upstate New York at 7 a.m. and travels to a middle school 14 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 that was reviewed by The New York Times. While Ms. Magrin’s identity was not disclosed in those records, The Times was able to easily connect her to that dot.
Like many consumers, Ms. 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.
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 United States — about half those in use last year. 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 analyze the data to cater to advertisers, retail outlets and even hedge funds seeking insights into consumer behavior. It’s a hot market, with sales of location-targeted advertising reaching an estimated $21 billion this year.
Businesses say their interest is in the patterns, not the identities, that the data reveals about consumers. They note that the information apps collect is tied not to someone’s name or phone number but to a unique ID. But those with access to the raw data — including employees or clients — could still identify a person without consent.
Many location companies say they voluntarily take steps to protect users’ privacy, but policies vary widely. Some companies say they delete the location data after using it to serve ads, some use it for ads and pass it along to data aggregation companies, and others keep the information for years.
Targeted advertising is by far the most common use of the information.
Source: Valentino-DeVries J., Singer, N., Keller H. M., Krolik, A. (2018, December 10). Your Apps Know Where You Were Last Night, and They’re Not Keeping It Secret. The New York Times.