Roland Moreno, the French inventor of smart card technology who died last week, once boasted he could stop any random person on a Paris street and find at least three examples of the technology in the person's pocket or purse.
Smart cards -- plastic cards embedded with an electronic circuit containing data that can be read and altered by a scanner -- have become so ubiquitous that Moreno could have safely made the same boast about London, Tokyo, New York or any other urban center.
From the commuter on a city mass transit system swiping his permanent rider's card over a sensor pad on a station turnstile to a shopper presenting a retailer's "gift card" to make a purchase to anyone in the world making a call on a SIM-card equipped cell phone, smart cards have exploded to the point where many of us easily exceed Moreno's expected three examples.
Credit and debit cards with "dumb" magnetic strips are being replaced by smart cards that can securely hold, maintain and update your account balance.
Medical identification cards can hold details of a person's health history, accessible by health care professionals when necessary.
In Europe, the insurance industry makes extensive use of them, and in Germany every citizen has a smart card for health insurance.
In the United States, several states use smart cards for applications ranging from department of motor vehicle licensing to electronic payments of government benefits.
Although many smart cards require insertion into a reader to be recognized and authorized, the use of contactless cards is growing for such high-traffic situations as mass transit.
The London Underground has its Oyster card, the Paris Metro system its Navigo and New York subway riders electronically load fare funds onto their MetroCards.
Multi-use smartcards are popping up as well.
In Hong Kong, a leader in utilizing smart card technology, people can use their Octopus cards not only for public transport but also to make electronic payments in stores, restaurants and parking garages.
In fact, the Octopus is rapidly becoming an all-in-one identification card used as access control in offices, apartment buildings and even schools.
A measure of its success -- and ubiquity -- is the fact that there are 19 million Octopus cards in circulation in a city with a population of 7 million, and more than 95 percent of residents between the ages of 10 to 65 use at least one Octopus card.
So if Roland Moreno were to reappear and stop you on the street, how many electronic circuits would he find you carrying about your person?
Cell phone? Bank card? Bus pass? Starbucks gift card?
So what's in your wallet?