Arvind Narayanan writes:
A 1993 New Yorker cartoon famously proclaimed, “On the Internet, nobody knows you’re a dog.” The Web is a very different place today; you now leave countless footprints online. You log into websites. You share stuff on social networks. You search for information about yourself and your friends, family, and colleagues. And yet, in the debate about online tracking, ad networks and tracking companies would have you believe we’re still in the early 90s — they regularly advance, and get away with, “anonymization” or “we don’t collect Personally Identifiable Information” as an answer to privacy concerns.
In the language of computer science, clickstreams — browsing histories that companies collect — are not anonymous at all; rather, they are pseudonymous. The latter term is not only more technically appropriate, it is much more reflective of the fact that at any point after the data has been collected, the tracking company might try to attach an identity to the pseudonym (unique ID) that your data is labeled with. Thus, identification of a user affects not only future tracking, but also retroactively affects the data that’s already been collected. Identification needs to happen only once, ever, per user.
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