Near field communication (NFC) is the set of protocols that enable electronic devices to establish radio communication with each other by touching the devices together, or bringing them into proximity to a distance of typically 10cm or less.
This APP illustrates how to read and write to an NFC tag using an NFC enabled android device.
The application of this is up to your imagination, you can use NFC technology for payments (Tap and Go), loyalty programs, access control, etc