What is Metadata? Simply put, metadata is information about other data. For illustration, think of a phone call (Figure 1). On the one hand, you have actual data, which in this case would be the spoken words exchanged in a call.
On the other hand, there are tons of metadata around the actual data, like the duration of a call, the geo locations of each participant, the volume during the conversation or even the phone models used by the callers. The phone call example also perfectly illustrates how powerful metadata can be. Research from the Stanford University, for instance, has shown that metadata of phone calls discloses a significant amount of personal information without accessing actual voice records.
Author: Julian Ereth