RFID was developed in World War II, helping radar operators distinguish friendly aircraft from enemy. By the 1980s it had evolved into wireless tracking and access applications and today provides omnidirectional electronic storage technology on chips that can read, write, store, and transmit data in freely available international frequency bands. In short, RFID chips are mini-computers that can wirelessly communicate.
In a futuristic bit of research, Dr. Mark Gasson, Senior Research Fellow at Reading University's Cybernetic Intelligence Research Group, has demonstrated the futuristic potential threat of human-implanted devices by implanting a virus-infected RFID chip below the base of his thumb. (Functionality of the chip provides him secure access to the building and his cellphone). Gasson then uploaded data from the chip to the server, which transferred over the virus.
Views differ as to the importance or intent of Dr. Gasson's research. For both viewpoints, see Man Infects Himself with Computer Virus, and Captain Cyborg Sidekick Implants Virus-Infected Chip.
At the very least, Dr. Gasson's research puts to rest the old question of whether RFID viruses are real or imagined.