What does that mean for you?
An address is a payment destination, not a promise of secrecy. Someone who knows that an address belongs to you may learn about payments associated with it.
A service may also know information about an account holder. Keeping a private key secret protects spending authority; it does not make the public payment history disappear.
Can you picture an example?
Imagine you post a receiving address on a public page with your name. A reader can connect that address with you. They do not need your private key to inspect public payment information.
What should you remember?
Privacy and security are related but different. An address can reveal information without letting a stranger spend your bitcoin. Avoid sharing payment details more widely than you intend, and do not assume a new account makes activity invisible.