You may or may not be aware of this term “NFC”. Here is a quick intro to the NFC.
Near field communication (NFC) is a set of standards for smartphones and similar devices to establish radio communication with each other by touching them together or bringing them into close proximity, usually no more than a few centimetres. Present and anticipated applications include contactless transactions, data exchange, and simplified setup of more complex communications such as Wi-Fi. Communication is also possible between an NFC device and an unpowered NFC chip, called a “tag”.
(cited from Wikipedia)
If you haven’t seen the Google Wallet, it is literally magical. Regardless the vibe, mobile payments technology is being around since early 2002. It was in a much smaller scale using near-field communications, more commonly known as NFC. The main idea behind Wallet is pay using your phone as a credit card (contactless).