Near-field communication, or NFC, is, I think, suddenly usable for normal people, in one very specific product: TecTiles, from Samsung. If you want a full primer on NFC, read this, but in short, NFC is a communications protocol, sort of like Bluetooth but without the need for elaborate searching and pairing. It's a tap-based connection: tap to connect to a speaker, tap to transfer data, tap to pay, tap to talk, tap to share. Eventually, this is the tech (or perhaps the basis of the tech) that'll let you replace your wallet with your phone. Credit card, gift cards, subway pass, identification, that'll all be digital, and you'll share it with a tap. But the infrastructure isn't nearly in place to do that smoothly, as Christina Bonnington of Wired found out when she went wallet-less for a month.