• The way we text: Tim Grant and other forensic linguists at the University of Leicester work on something called “forensic authorship analysis“. They basically analyze the way people write text messages on their mobile phones. Apparently, these techniques already play an important role in providing evidence in criminal cases (examples here and here).

• The way we click: In a recent working paper, Balaji Padmanabhan and Yinghui Yang ask whether there is something like a “clickprint” – a unique pattern of surfing behavior based on how long you visited what websites at what time of the day and other actions. They conclude that it is in fact possible to distinguish two persons based on clickstream data, given the optimal level of aggregation as computed by their method.

• The way we walk: Researchers at GeorgiaTech work on “Human Identification at a Distance.” Their focus is on gait recognition and the way we move as an “activity-specific biometric.” They propose “a technique that recovers static body and stride parameters of subjects as they walk.” (No, they have nothing to do with these guys.)

Even though privacy advocates are likely to loose some sleep over such possibilities, one could – perhaps a bit sarcastically – argue that there is also a good side to it: it seems to become harder and harder not to be unique.