Retailer Overstock experienced a glitch in their system that allowed customers to pay for goods using Bitcoin Cash rather than Bitcoin, which is valued at a fraction of what Bitcoin is. Overstock’s website gave customers the option to pay with either Bitcoin or Bitcoin Cash interchangeably. Although a seemingly small error, the two cryptocurrencies hold vastly different values. Customers taking advantage of this mistake would also have had the possibility of cancelling the order and being refunded in Bitcoin, making a profit as a result.
Data provided by bitcoinist.com