Subways and airport parking facilities in San Francisco, Washington DC and New York are using them. The State of Oregon will use Smart Cards for Food Stamps. Local banks are probably next. Some information can only be added and not erased. Stand alone telephone cards will tick off internal registers until pre-paid time is used up.
Telephone cards can be self-contained and disposable.
They can also be small removable sim chips or reprogramable cards. Portland's Voicestream PCS phones use cards that activate an account, store your PIN number and remember incoming and outgoing phone numbers. Soon, Internet smart cards may put money on your local hard drive . Digital serial numbers prevent counterfeiting. Smart Cards are a new technology and will likely have a significant influence on society and the way we do business.