Just because it's not unique doesn't mean it's not personally identifiable. For instance, you can quite often uniquely identify a person given their date of bi

Just because it's not unique doesn't mean it's not personally identifiable. For instance, you can quite often uniquely identify a person given their date of birth, gender, and zip code, none of which are nearly as unique as a MAC address[1]. Even the combination of these factors results in < 2 billion unique permutations, whereas the MAC address space numbers in the hundreds of trillions. That means, given a MAC address, I can narrow narrow down the "who" to a fairly small set of people. Add in even one other piece of scraped info, and you've got a pretty high level of uniqueness. [1] http://godplaysdice.blogspot.com/2009/12/uniquely-identifying-people-by-birth.html http://godplaysdice.blogspot.com/2009/12/uniquely-identifyin...