[hnuser77]

There is a conceivable way for actions outdoors to be private. Just roll back the clock a whopping 3 decades. Maybe nosy old Ethel notices when you leave for work in the morning, but she's not tracking your face's position and emotion across the city. Your location and reading history is not being recorded from your cell phone and logged permanently. Would it bother you to send me your exact GPS coordinates right now, or if I dispatched a drone to follow you around at all times the instant you stepped outside your front door, then post the video feed on the internet?

There are multiple billion-dollar companies whose entire business is tying together data from all these disparate systems, e.g. Palantir. There are leaked multiple government programs whose entire purpose is the same, e.g. XKeyscore. Or look at something more general purpose like Splunk, where it is trivial to filter 1TB of logs from different sources and map identifiers.