Tony Gallippi, the boss of Bitpay, which processes Bitcoin payments for retailers, says that his client list has increased from around 100 in March to 1,100 now. These are mostly e-commerce businesses, selling things like domain names and web hosting. But the list also includes a taxi-driver in Chicago and a dentist in Finland. "Credit cards weren't designed for the internet," he says. Bitcoin transactions cost less and cannot be reversed in the way credit-card transactions can be. This is important for firms selling to customers in countries known for credit-card fraud, such as Russia or Belarus.