From FaceBook to SockBook
Since most privacy-aware people would never accept carrying an NFC tracking device (e.g. on his ID card/passport), why not devise a way to have the geeks wear them and be proud of them? I wouldn't be surprised if in the near future all kinds of shops gave the socks (or other NFC-enabled clothing items) away as "gifts", since in the long term it would allow the global tracking the owner of the credit card that made the purchase.
An additional benefit is that sock NFC detectors can be embedded in the floor and not be visible. Sniffing socks has acquired a whole new meaning.
First thing Monday morning, I'm going to patent a new generation of shoes lined with tinfoil and gain millions by just licensing the patent!