In March 2012, an account named "tempaccount987" posted on Hacker News with the title: "Apply with me to YC in the next 3 days and change the world". I'll post it in the first comment.
That account turned out to be Brian Armstrong, and the company resulting from that post turned out to be Coinbase.
But at the time, it was called Bitbank, with a prototype no more complicated than what you'd find in a beginner web development tutorial.
FMI:
