There's a line to be drawn between, "privacy from people who are actively looking at you to find something about you" and "privacy from computer algorithms that will make decisions about you based on your personal activities"

Whilst it is likely that you will get "lost in a sea of people" for the most part, it's also quite likely that you will "stick out" in one way or another and this might not be in a way you like or even in a way that is necessarily fair.