Stanford, V. “Pervasive Computing Goes the Last Hundred Feet with RFID Systems,” IEEE Pervasive Computing, Vol. 2, 2 (April-June 2003), 9-14  
ID tags, as RFID technology has come to be known, are low-power, short-range communication devices that can be deployed in quite different environments and various contexts. Low-end passive tags have approximately 32 bytes of local storage and are powered by the RF field generated by the readers. High-end tags can have full-blown microcontrollers and multiple interfaces to the environment, with local batteries to power them. These tags are far more versatile than product bar codes. These tags can be

• Scanned without first establishing the line-of-sight,
• Scanned many at a time,
• Scanned and captured data far more than what is embedded on the printed bar code,
• Scanned and updated,
• Interfaced to different sensors and devices.

Applications include (given in the article):
• Access control: RFID tags embedded into personal ID cards,
• Baggage ID: Passive tags embedded in paper luggage tags,
• Automotive systems: Keyless entry and immobilization systems,
• Document tracking: Passive tags affixed to ducments,
• Express-parcel tracking: FedEx tags drivers and packages for various purposes,
• Library checkout and check-in: Passive tags in books,
• Livestock or pet tracking: Tags injected into pets, aiding recovery when they are lost,
• Logistics and supply chain: Container and product tracking,
• Wireless commerce: Speedpass and E-ZPass pay tolls and gasoline purchases.