MIT asks the question in an article about how much information individuals create about themselves.

Much of this data is invisible to people and seems impersonal. But it’s not. What modern data science is finding is that nearly any type of data can be used, much like a fingerprint, to identify the person who created it: your choice of movies on Netflix, the location signals emitted by your cell phone, even your pattern of walking as recorded by a surveillance camera. In effect, the more data there is, the less any of it can be said to be private, since the richness of that data makes pinpointing people “algorithmically possible,” says Princeton University computer scientist Arvind Narayanan.