The bold prediction comes as Paypal announces that it now has more than 100 million active accounts worldwide.

"Consumers are increasingly giving up traditional payment methods such as cash and cheques and turning to a more modern - and anytime, anywhere - form of payment," says PayPal president Scott Thompson. "We believe that by 2015 digital currency will be accepted everywhere in the US - from your local corner store to Walmart. We will no longer need to carry a wallet."

To celebrate the 100 million account milestone, Paypal has invited five Bay Area employees to ditch their wallets and use only digital currency to pay for all their purchases.

Finextra verdict It's a bold assertion, but what, exactly, does Thompson mean when he refers to digital currencies? Are we talking Bitcoins? Facebook Credits? Or just a souped-up version of old-fashioned money in a snazzy new form factor, like a mobile phone, or, erm, a plastic card?