This week has seen a flurry of articles on the Facebook Photo Tagging feature after the security firm Sophos posted a story on its blog noting that this feature, which had previously been limited to North American users, had now been extended to other regions. The Photo Tagging feature makes it easier for users to tag their friends in a photo. Initially, this feature required users to label every photo manually. Not surprisingly users asked for an easier way to do this and Facebook responded with...

In a recent Politico op-ed Rep. Jackie Speier (D-CA) wrote, “Online trackers claim the information they collect is anonymous and helps enhance the user’s experience. But that doesn’t tell the whole story. The truth is it only takes 33 ‘bits’ of information to uniquely identify someone.” While she was certainly not the first one to make this statement (indeed Arvind Narayanan at Stanford dedicates his blog “33 Bits of Entropy” to this topic), this assertion—that individuals can be identified with...