Watch out where you go and who you go with.  WiFi can now be efficiently used for high-resolution mobility tracking of people, groups of people and entire populations.  Wifi signals can detect where people go, who people go there with and not only who is there but who is interacting with whom according to a recent University of Denmark study found.

But tracking can go one stop further by monitoring the ‘physical proximity between pairs of individuals’ by looking at the Wi-Fi signals they both pick up.  For example, the system can track when two users are picking up the same Wi-Fi signal which suggests that they are in the same place.  Read more