Dries Depoorter built software to scan online public cameras and link them to geotagged instagram posts from the same location. Basically finding people from a single instagram photo and potentially tracking them across any public (or not) camera out there. Technically impressive, yet disturbing.
There was a video on the page too, but it seems to have been pulled due to a copyright claim from Earthcam who, I imagine, weren't very happy about their cameras being used for this.
The world is slowly catching up to dystopian sci-fi stories. A predictive policing program used by Chicago's police predicted a man would be involved in a shooting. The ramifications within the police and local community ended up getting him shot – twice!