The National Security Agency, along with its British counterpart, the GCHQ, can exploit sometimes very personal data that leaks from popular phone apps.
That's according to The New York Times, which is basing its reporting on secret British documents obtained by former NSA contractor Edward Snowden.
According to the Times, the NSA and GCHQ have "traded recipes for grabbing location and planning data when a target uses Google Maps, and for vacuuming up address books, buddy lists, phone logs and the geographic data embedded in photos when someone sends a post to the mobile versions of Facebook, Flickr, LinkedIn, Twitter and other services."
Not only that but the agencies can also scoop up data as it moves across the stream. When one person updated the Android software on their phone, for example, the agencies captured "nearly 500 lines of data about the phone's history and use onto the network."
As Times puts it, this kind of data is normally used by mobile ad companies to create detailed profiles of phone users. From this data, the ad companies are able to discern where people travel, "what apps and websites they open" and might be able to "triangulate web shopping data and browsing history to guess whether someone is wealthy or has children, for example."
It's important to note that the Times piece talks about capabilities, not necessarily what the NSA and GCHQ are doing. While it's clear the spy agencies are scooping up data, it's unclear the extent or how much of it is coming from Americans.