And its value has skyrocketed in recent months.
Last week, Bloomberg.com columnist Paul Ford opined they could now be the world's last currency safe haven.
But many readers at this point are probably wondering ... what exactly is Bitcoin?
Robert McNally, an iOS developer at parking payment startup QuickPay, gave the following presentation to last year's Hackers' Conference (don't worry, they were the "good" kind of hackers) in Santa Cruz, answering exactly that question.
With his kind permission, we have republished it here.