Almost everything you use was built open. Not broken, not compromised. Open, deliberately, because someone else's business model depends on being able to read it.
Four surfaces account for most of the exposure: the mail you send, the network you send it over, the conversations you believe are private, and the device holding all three. What follows is what each one actually gives away.
The mail
Consumer mail is not a postal service with a screen attached. It is an advertising business that happens to deliver letters, and the arrangement is disclosed in terms almost nobody finishes reading. Your correspondence is parsed by machine before it reaches you, so that the contents can inform what is sold to you and about you.
The message body is only half of it. Who wrote to whom, at what hour, how quickly you replied, and how often you two correspond describes a relationship perfectly well without a single sentence being read. A bank, a clinic, a law firm and a divorce solicitor each have distinctive sending patterns.
Then there is the part most people have never been told. A large share of commercial mail arrives carrying an invisible marker, a single transparent image loaded from a remote server the instant you open the message. The sender learns that you opened it, roughly where you were, on which device, and how many times you returned to it. You did not click anything. You read your mail.
The network
Encryption protects what you say. It does not conceal that you said it, to whom, or for how long.
Every connection your household makes leaves a record with whoever carries the traffic: which services, at what times, in what volume, from which premises. The lookup that translates a name into an address is frequently still sent in the clear. A viewer with no access whatsoever to your messages can assemble your working hours, your travel, your medical enquiries and your professional relationships from the pattern alone.
Meanwhile the house itself is talking. Televisions, thermostats, speakers, doorbells, cars and watches all report back on a schedule, to manufacturers with their own commercial interests and their own breach histories. A residence today is a small, permanently connected fleet, and almost none of it was purchased with a threat model in mind.
The conversations
A great many platforms can read what is sent through them. Some say so. Where end-to-end encryption is genuinely applied, the protection is real and worth having, but it is narrower than the marketing suggests.
The provider still holds the directory: who you are connected to, when you are active, which groups you belong to. Encryption is also routinely undone at the edges, because a convenience feature copies conversations to a general-purpose cloud account, where they sit in a form the provider can access and a court can request. The chain is only as strong as the least deliberate setting in it.
And an encrypted conversation is still readable over the shoulder of a compromised handset, which brings us to the part that governs everything else.
The device
Every protection above assumes the machine is sound. If it is not, none of the rest matters. A device reading your screen does not need to break encryption; it simply waits until you have decrypted the message yourself.
A mobile handset as sold is an instrument of continuous measurement. Location, movement, application use, network history and identifiers stable enough to follow you across services are collected as a matter of ordinary operation, by the operating system and by nearly every application on it. Much of this can be reduced. Very little of it is off by default, and the settings that govern it are numerous, renamed between releases, and quietly restored by updates.
This is why device integrity, rather than any individual application, is the foundation of the whole structure. Sovereignty over your digital life is decided by whether the thing in your pocket answers to you or to someone else.
What closing it actually takes
Not an application. There is no purchase that resolves this, which is precisely why the market is full of them.
It takes a device procured and configured deliberately, with telemetry severed at the system level rather than switched off in a menu that an update can switch back. It takes each step verified by a person who can explain why it is there, not a script run over a handset. It takes that work done in the room, hardware in hand, never shipped and never performed remotely. And it takes a household reviewed as a whole, because the most carefully configured phone in Europe is of limited use beside an unconsidered television and a family calendar shared with twelve people.
None of this is exotic. It is unglamorous, methodical, and largely a matter of refusing the defaults. What it produces is a life that is closed unless you open it.