There's lots of unfounded fears for facial surveillance. Recall the artist who is making plastic masks to 'stop' Chicago's imaginary facial surveillance system.
However, the US NSA may really be on to something with their emerging effort.
The NYTimes is reporting on Snowden documents that claims the NSA is doing large scale harvesting and analysis of pictures on the web:
"The agency intercepts “millions of images per day” — including about 55,000 “facial recognition quality images” — which translate into “tremendous untapped potential,”
This sounds both very believable and practically useful.
Unlike video surveillance images, which due to problems with angle of incident, insufficient pixel density, and lighting limitations, are rarely viable for effective facial recognition matching, the web features lots of high quality, direct, head on shots of people that work well for this application.
It, of course, depends, where the NSA is getting these images (Facebook, Instagram, Vine, etc. ?) to determine how wide a net they are casting but the fundamental approach is very likely to help them track / match individuals.