ZDNet has an article about the implanted RDIF chips and the debate about its pros and cons.

Advocates of technologies like radio frequency identification tags say their potentially life-saving benefits far outweigh any Orwellian concerns about privacy. RFID tags sewn into clothing or even embedded under people's skin could curb identity theft, help identify disaster victims and improve medical care.

Critics, however, say such technologies would make it easier for government agencies to track a person's every movement and allow widespread invasion of privacy. Abuse could take countless other forms, including corporations surreptitiously identifying shoppers for relentless sales pitches. Critics also speculate about a day when people's possessions will be tagged - allowing nosy subway riders with the right technology to examine the contents of nearby purses and backpacks.

The notion of embedding RFID tags in the human body, though, remained largely theoretical until the 11 September, 2001, terrorist attacks, when a technology executive saw firefighters writing their badge numbers on their arms so that they could be identified in case they became disfigured or trapped.

Richard Seelig, vice president of medical applications at security specialist Applied Digital Solutions, inserted a tracking tag in his own arm and told the company's chief executive that it worked. A new product, the VeriChip, was born.