To be clear: the article claims that Facebook can recognize anyone just by seeing them. They haven't demonstrated this ability.
It's far easier to judge who's in your picture among your 20 closest friends than it is to find that face among all two billion Facebook users.
State of the art recognition systems still have a few orders of magnitude of accuracy improvements to go before they can solve that problem.
See the Iarpa Janus project for some recent government+academic-sponsored work on this front: http://www.nist.gov/itl/iad/ig/facechallenges.cfm The task is to recognize terrorists in airport surveillance pictures and such.