Snowden gets into a particular aspect of privacy, skip to 1:35:58, where the ownership of data becomes important to the courts.
What it boils down to is, the courts can nail you with data collected by a third party because you don't own this data. Sometimes we talk a lot about "owning your own data," but usually in the context of ads and non-criminal topics.
Instead, this part of the US law pertains to what is available to law enforcement without a warrant. If you could own and silo your own data, then this avenue of attack by government would at least be more difficult. In theory, they'd have to get a warrant. I'm not saying it would be a silver bullet against government intrusion.
You hear about this every so often on the non-criminal side. People who want to broadcast without needing permission will collect e-mail addresses and use independent, low-tech systems to broadcast their message.
What they're doing is collecting and siloing their own e-mail lists because it ends up being more reliable than having social media or clouds maintain contact information for you.
Here we are, in 2020, and e-mail lists are still the preferred broadcast method (at least for paranoid folks).
With the above in mind, wouldn't it be great if there was a way to default your online profile as hidden, and any lookups that people or apps want to do had to go through a "DNS" that you controlled?
One way this would work is for you to get on the internet with a VPN enabled, all the time. By default, your OS won't let you access the internet unless you're behind a protected network layer. Then, if you want to identify yourself to the remote service, you give that service authorization to execute a smart-contract.
So if someone wants to call you on the phone, the person calling can access the contract to get your current data and the call can be placed.
I only mention a smart contract because I wanted to include a decentralized solution. Maybe there's another way to do it. But the point is, you authorize access on an opt-in basis and that basis can be revoked.
Even if you don't revoke access, the data about access is encrypted and stored for you. Remote data providers only store the authorization and thanks to the VPN, the current data will be outdated in a short period of time. They'd have to keep asking for the current data in order to know about you on an ongoing basis, which you are free to revoke.
Anyway, the point I'm trying to make is that systems can be implemented to ensure you own your own data. Some of those systems are available now and some of them need to be invented.
If you watch the full video above, you'll understand why regular people would want to do this.
