You can be identified by your heartbeat and your gait. You can be identified by your fingerprints and iris patterns. And you can always be identified by your smartphone broadcast unique number called MAC addresse.
And more things that identify you as well: your phone number, your credit card number, the license plates on your car.
Once you are identified, the data about who you are and what you are doing can be correlated with other data collected at other times.
This might be movement data, which can be used to follow you throughout your day. It can be purchasing data, Internet browsing data, or data about who you talk to via email or text.
It might be data about your income, ethnicity, lifestyle, profession and interests.
There is an entire industry of data brokers who make a living analyzing and augmenting data about who you are - using surveillance data collected by all sorts of companies and then sold without your knowledge or consent.
Modern mass surveillance has three broad components: identification, correlation and discrimination.
It is not just that they know who you are, it is that they correlate what they know about you to create profiles about who you are and what your interests are.
What is important to them is that you can be consistently identified over time.
The problem is that you are being identified without your knowledge or consent, and Society needs rules about when that is permissible. We need new rules.
We need better rules about when and how it is permissible for companies to discriminate. Discrimination based on protected characteristics like race and gender is already illegal, but those rules are ineffectual against the current technologies of surveillance and control.