> You choose to tell the doctor private information because of patient-doctor confidentiality. The other type of “private information” is collected by observing

> You choose to tell the doctor private information because of patient-doctor confidentiality. The other type of “private information” is collected by observing you in public (e.g. in a Walmart). I think this distinction is irrelevant. The salient questions are: - Is this information private and potentially damaging to me? - Do I expect [third party] to have access to it? This is especially important if [third party] can be a government. In the massive web of interconnected buyers/sellers of adtech data, there is no reason to expect that oppressive governments will be unable to get anything they want. But to address your point: I absolutely do not expect "observing in a public place" to include personal conversations and/or data about exactly what products my eyes land on.