What zero-knowledge actually means
Zero-knowledge means the service can move your data around without being able to read it. Your browser creates the encryption key, transforms the message locally, and sends only encrypted ciphertext to the server. That keeps the trust boundary small and makes a breach far less damaging.
For people sharing passwords, notes, or API keys, this matters because the service never becomes a readable copy of the secret. You are not asking a vendor to keep your data safe for you. You are using the vendor as a delivery channel for encrypted content.
Why it is a better model for secrets
Secrets are different from ordinary content. A private note is useful only when a human can read it, but a malicious actor can extract value from it immediately. If the server cannot decrypt the payload, a database leak is much less catastrophic.
This also makes the product easier to explain. The promise is simple: the browser handles encryption, the server handles storage and delivery, and the key stays with the user. When that workflow is implemented correctly, the platform never needs to know what the secret says.