| Version | Currency | Form |
| 0 | None | 'Garden of Eden' |
| 1 | Barter | Direct exchange of goods and/or services |
| 2 | Token | Gold, silver, shells, barley, [share certificates] |
| 3 | Money | Notes or coins backed by gold, silver etc |
| 4 | Fiat | Notes or coins not backed by gold, silver etc |
| 4.1 | Global | SWIFT, Western Union |
| 4.2 | Card | Credit card, debit card, stored value card |
| 4.3 | Online | PayPal, card payments, online funds transfer |
| 4.4 | App | Ewallet, QRcode, NFC, digital bank |
| 5 | Crypto | Bitcoin, Ethereum, IOTA, Ripple, Libra |
Functions of Money
- Medium of exchange - Accepted for payment for goods and services
- Unit of Account - A hotdog cost $1 and a Tesla $35,000
- Store of Value - Can be saved in a bank (or tin box) and used later
Properties of Money (Classical) 1
- Fungible - Any dollar note is the same value & exchangeable with any other
- Durable - The note (or coin) does not wear or tear easily
- Portable - Can be readily carried from place to place for reasonable amounts
- Recognisable - And able to easily distinguish $1 from $5 from $10 etc.
- Stable - Hotdog doesn't cost $1 one day, $10 the next and 20¢ the day after.
Properties of Money (Crypto 1.0)
- Anonymous - 'Can buy weed' (preserve privacy)
- Immutable - Once paid, it is paid, cannot be reversed
- Decentralised - Not controlled by authorities
- Programmable - Automatic contracts.
Properties of Money (Crypto 2.0?)
- Accessible - Easy onboarding (no need specialised knowledge or procedures).
- Sovereign - Not readily banned or money withheld ('like with PayPal')
- Liquid - Widely accepted for online and offline payments
- Safe - Does not naturally attract scams
- Fast - Near instant transaction confirmation