[Editor’s note: Earlier in the interview, Narayanan had mentioned that the rate at which your battery depletes might be an identifier.] But let’s say you’ve got 41 fonts installed on your browser today. You come back in a week, maybe you have 43 fonts installed. But 41 of those are going to be the same as what they saw a week ago. And it changes slowly enough that statistically you can have a high degree of confidence. In the industry they call these things statistical IDs. It’s not as certain as putting a cookie on your browser, but you can derive a very high degree of confidence.
--Arvind Narayanan, FiveThirtyEight, on the shrinking private domain