Exactly, and I think we're usually way off intuitively. For example when considering how many facts of what nature I'd need to individually identify you. SSN?

Exactly, and I think we're usually way off intuitively. For example when considering how many facts of what nature I'd need to individually identify you. SSN? Ok, done, everybody knows that. But how far do I get with birth date, height and city? What if I add one chronic health issue, no matter how small? Chronic sinusitis, born on August 8th, lives in $city and is 186cm? In most cases, I probably don't even need all four. But most people intuitively don't think about it in combination, they figure "oh so you know I live in $city, big deal, so do a million other people", "oh so you know my birthday, well a million other people in the country have that birthday".