There's an entire industry that revolves around tracking people's movements via their smartphones and selling that data to third parties. It's legal (in the U.S.), it isn't particularly hard to do, and while the data is supposed to be anonymized, it's often easy to connect it to a real person.

For smartphone owners, this is very tough to avoid, especially for a non-technical user. If you own a smartphone, you're probably one of many dots on a map, stored on a server of a company you likely never heard of.

This is according to a new analysis by The New York Times, which examined a data file containing 50 billion location pings from the phones of more than 12 million people in the U.S. The data file, which the NYT claims is "by far the largest" ever reviewed by journalists, has been provided by anonymous sources, and it does not belong to the government or a telecom company.

This data, which can be legally bought and sold every day, paints a detailed and deeply personal map of every day of your life, including :



- Your kid’s exact route to school

- Where you spent the night, or potentially even whom you spent the night with pic.twitter.com/yrIbSZi2Ki — New York Times Opinion (@nytopinion) December 19, 2019

Instead, the data comes from many location data companies, which track user movement via software installed on their phones, whether they know it or not. Some of these companies, like Foursquare, have familiar names. Others, like Inrix, Skyhook and PlaceIQ, are probably unknown to the vast majority of people.

While the data is anonymous, the analysis shows that it's easy to connect one dot on a map to a real-life identity —and previous research indicates the same thing. A simple example would be your daily commute: You likely make the trip from your home to office and back every day, so if a smartphone makes that same trip every day, it's probably carried by you.

The NYT says it easily tracked visitors to locations such as the Playboy Mansion, Johnny Depp's estate, and President Trump's Mar-a-Lago resort in Palm Beach.

"With the help of publicly available information, like home addresses, we easily identified and then tracked scores of notables. We followed military officials with security clearances as they drove home at night. We tracked law enforcement officers as they took their kids to school. We watched high-powered lawyers (and their guests) as they traveled from private jets to vacation properties," the report says.

Factual, one of the data location companies mentioned in the report, says it does not resell detailed data like the data described in the report, and Foursquare claims the same thing. It's obvious that some others do, though, and there's currently no law preventing it. Even if the data is not sold, there's still a risk of a hacker obtaining it and using it for nefarious purposes, or selling it on the darknet.

The conclusion is simple: If you want to enjoy the convenience of a smartphone — and life today is almost unimaginable without one — you're being tracked. Anonymization of this data doesn't help matters much, so until regulations change, the data will be easy to abuse.

The full report is well worth the read, and NYT's graphics provide a great sense of scale on just how far this surveillance goes. Check it out here.