I just had an idea that I think would be excellent for increasing bitcoin popularity among merchants.
I'm selling something that I charge £100 for, but I also take bitcoin as payment and the buyer chooses to pay using bitcoin. I use an exchange's API to query the buy orders and calculate how many bitcoins I would need to immediately sell in order to earn £100. This is the cost of the product in bitcoins. The buyers sends that amount of bitcoins directly to the exchange using the sellers deposit address and the coins are automatically sold immediately. Once the coins have been sold, the exchange notifies the merchant and the merchant completes the buyer's order.
This would require the bitcoin client to allow you to enter a reference number and send it as a comment.
What an exchange could do to help with this.
- Implement a new api call that takes a currency value as its parameter and returns a bitcoin value. The bitcoin value is the number of bitcoins that would need to be immediately sold to earn the specified currency value.
- Implement functionality that allows bitcoins to be automatically sold as soon as they are deposited. In the case of confirmations being required, the coins could be "virtualy" sold until the required number of confirmations has been met. The buy orders would be temporarily removed until then and if the deposit could not be confirmed, the buy orders would be reinstated.