And it's a growing industry worth an estimated $12 billion, involving aggregators, collectors, marketplaces, and location intelligence firms.

Companies profiting on location data fly under legal radar

A location firm called Near labels itself "The World's Largest Dataset of People's Behavior in the Real-World," featuring data consisting of "1.6B people across 44 countries." Another company, X-Mode, claims it has data representing "25%+ of the Adult U.S. population monthly," whereas Mobilewalla brags about its access to data from "40+ Countries, 1.9B+ Devices, 50B Mobile Signals Daily, 5+ Years of Data."

TNW's "The Markup" identified 47 different companies that collect, sell, or trade-in the location data from mobile phones, according to the report. And this list begins to illustrate the situation of mass surveillance: an interconnected, collaborative group of companies that offer code to app developers, monetize user data, and sell analytics from "1.9 billion devices", enabling access to datasets from hundreds of millions of people. Just six of these companies hold data from more than 1 billion devices, and at least four other firms say their data is the "most accurate" in the industry.

"There isn't a lot of transparency and there is a really, really complex shadowy web of interactions between these companies that's hard to untangle," said Cyber Policy Fellow Justin Sherman, at the Duke Tech Policy Lab, in the TNW report. "They operate on the fact that the general public and people in Washington and other regulatory centers aren't paying attention to what they're doing." And, sometimes, the industry is exceedingly invasive. A 2020 report from Motherboard showed how X-Mode, which gathers location data via apps, was collecting data specifically from Muslim prayer apps, and then selling them to military contractors. That same year, the Wall Street Journal reported how Venntel, which provides location data, sold location data to federal agencies, for the purposes of immigration enforcement.

The list goes on.

A multitude of firms say privacy is of primary concern, emphasizing that they take great care to never sell information that could reveal the identity of a person. But this can be misleading, as recent anonymized location data studies have shown. The hard fact of modern life is that there's no clear way to know the ways your movements are tracked, traded, and monetized. Companies typically don't announce which apps supply collected data, or what kind of data they grab, where it goes, or when. Building an image of the new information ecosystem, TNW's The Markup reviewed the marketing language of the 47 companies, and traced how the data from your phone enters and moves through the information ecosystem.

The personal-phone-to-monetized-data pipeline starts in our hands, when you get a notification that asks for your permission to access location data. This isn't entirely suspect, since apps about weather, wind, or maps can't really perform their function without knowing where you are. But some of these apps sell and share that location data to companies that analyze and use it for profit. Advan Research does this. But others, like Adsquare, buy or trade their way into possession of the data from various apps to aggregate it with other sources. For many apps that ask for location, it's easy for users to opt out and avoid the risk. But even the apps that feel most essential and benign could be sources for these companies, who don't share their sources, to maintain a competitive advantage. Time will tell how our location data is used in the coming years, and whether new laws might prohibit this increasingly high-tech market that's at once everywhere and nowhere.