RFID describes a group of wireless technologies very similar to barcodes. However where you need to see a barcode to read it, with RFID you don't. Indeed with RFID you most often cannot see the barcode equivalent of the scanner nor the barcode. These are the two principle reasons why most RFIDs go completely unnoticed.
RFIDs can be very simple or have different security features allowing their use as contactless Bank cards or, tickets or, identity documents. In fact there is a whole range of different technical features and characteristics which allow RFIDs to be tailored to their purpose or application.
For those wishing to know more about the breadth of technical characteristics encompassed by RFID, please refer RFID&U’s Links page.