Daniel Ameli is a data scientist and cryptocurrency expert who has written extensively about Bitcoin.

Failed, raided and fraudulent Bitcoin exchanges have included Mt. Gox, Bitomat, MyBitcoin, Bitcoinica, Bitcoin Savings and Trust, Bitfloor, Instawallet, Bitcoin Foundation, Inputs.io, Global Bond Limited, Flexcoin, Bter, Bitstamp, Cryptsy, Gatecoin, Bitfinex, and NiceHash.

Aristotle defined money as follows:

* It must be durable. Money must stand the test of time and the elements. It must not fade, corrode, or change through time.

* It must be portable. Money hold a high amount of ‘worth’ relative to its weight and size.

* It must be divisible. Money should be relatively easy to separate and re-combine without affecting its fundamental characteristics. An extension of this idea is that the item should be ‘fungible’. Dictionary.com describes fungible as: “(esp. of goods) being of such nature or kind as to be freely exchangeable or replaceable, in whole or in part, for another of like nature or kind.”

* It must have intrinsic value. This value of money should be independent of any other object and contained in the money itself.

The BBC’s More or Less programme estimated that a Bitcoin transaction costs more than 50 times that of a credit card transaction.