So if you're encrypted, you're good right? Not so fast. Every digital interaction online creates something known as metadata. Metadata is everything but the message, which means it includes when, where, and who you are talking to, and even how much. Metadata is created every time you send an email, make a phone call, or visit a website, because even if nobody is logging the content of what you are doing, someone is probably recording metadata.
This metadata can be stored by your internet provider, your cell carrier, the messaging apps you are using, your VPN service... your metadata is everywhere.
Read this from the EFF on why metadata matters: https://ssd.eff.org/en/module/why-metadata-matters
How much does metadata matter to you? Well you can make that decision based on your threat model. If you don't want people to know who you are talking to and how often, metadata matters.
As former Director of the NSA and CIA, General Michael Hayden once said "We kill people based on metadata". That's more of a problem for terrorists than you, but metadata fits into some people's threat profiles.
- Describe the metadata created by you connecting to Facebook and sending a picture of yourself to your friend.