The remarkable take-home from my infrequent exposure to Facebook (et al.) is that the children of the 21st century (like my sister's kids) will grow up alongside a large database of photographs of them having metadata identifying each person in that photograph. Their parents' generation are also now retrospectively identifying the faces in their own photographs of themselves and their associates. Speeding the process up, Facebook now has automatic face tagging enabled by default. Apple's iTunes has had this feature for a few years already, as has Google's Picasa.
Secondly, the current crop of cheap-as-dirt point and shoot cameras has amazingly good and fast face detection. If there aren't already security cameras that can do "find the faces in this video feed, then quickly pan/zoom to frame and capture each face in turn", you can bet there will be real soon; casinos and pubs will be all over that, as will countries like Australia and Britain, plus every fascist dictatorship everywhere. Captured photos can then go to offline face-detection. Cellular phones are already effective tracking devices, but you can always leave your phone at home.
The final piece of the panopticon dropped into place with Apple's iCloud -- automatic uploading of photographs over wifi. You can bet pretty much every camera brought to market from now on will do this.
- Several massive databases of face-tagged photographs (Apple's, Google's and Facebook's)
- Most consumer cameras uploading pictures to the cloud in near real time
- Municipal face-harvesters (sorry, "safety cameras")
- Government access (overtly or covertly) to all of the above databases
You have crowdsourced real time tracking of EVERYONE and a near total database of their KNOWN ASSOCIATES, without governments having to legislate for it, or even issue identity cards. It wasn't necessary for the Evil League Of Evil to plan this, it just emerged from the market. And it's too late to get un-fucked.
False positives, the big point of failure in previous attempts at the face-scanning panopticon no longer matter so much; if you want to know who was at a given event, or where person X is now, the side channel data from cellphones and social connections can be used to winnow through the partial matches. If you have an 80% match for person X and also for 3 of their friends at one event, (or if their cellphone is known to be in the same general location) then the match can be confirmed without human intervention.
So, remember to wear your dazzle paint when you go out, OK?!