In reply to Ryan Hellyer.

Development of this project's core technology launched about 6 months ago as a proof of concept to be used on network of private blogs. Idea itself - about year ago. And original Hashcash was invented by Adam Back in 1997 - check http://hashcash.org/. There are also couple hashcash-like based plugins on wordpress.org (just search by hashcash keyword)

I.e. idea is definitely not new, but there are no wide-used implementation yet. Hashcash.IO is just one of these implementations and time will tell if it is good.