Currencies have existed in a huge variety of forms over time. Basically anything can work as a medium of exchange as long as everyone has a high degree of confidence that if they are paid in the currency, that they too can pay someone else in that currency. But that's not to say all currency regimes are created equally -- we've learned a number of lessons, painfully, about how to manage currencies. For a small-scale,…
The one problem associated with gold that it does solve is being as good a medium of exchange as visa/paypal (or better).