It’s like what’s on the envelope.
Theoretically, metadata isn’t about the content of your messages, just the external details. But even that can tell you a lot – where it’s from, who it’s addressed to, how heavy it is. From that, you can start to identify the content – if it’s from a bank, it probably isn’t a love letter. Most digital metadata contains extra nuggets – the software you use, the top line of content, the IP address that can be matched with other online activity. So it can be a fairly transparent envelope.