E-cash spreads its tentacles

Mrs Chen probably doesn't realize the significance of her new Octopus card. She leaves it in her handbag and holds it by the turnstile. She passes through, and it deducts the fare. She catches her train and thinks nothing more about it.

However, Mrs Chen and the four million other Hong Kongers who hold Octopus cards are part of a monetary revolution. The Octopus system has created HK$4 billion ($516 million) of electronic money in an economy with about HK$100 billion of notes and coins in circulation.

Something similar is happening in Singapore. As motorists drive through the city at peak times, a charge is automatically deducted from a removable smart card installed in their cars. To enter central Singapore they need to charge the cards, which can also be used to make purchases in shops, with electronic money.

In these two city states, a critical mass of...