The NSA calls this “metadata.” The term’s prefix, “meta,” which traditionally is translated as “above” or “beyond,” is here used in the sense of “about”: metadata is data about data. It is, more accurately, data that is made by data—a cluster of tags and markers that allow data to be useful. The most direct way of thinking about metadata, however, is as “activity data,” all the records of all the things you do on your devices and all the things your devices do on their own.
