Today, we are officially introducing a proof-of-work (PoW) defense for onion services designed to prioritize verified network traffic as a deterrent against denial of service (DoS) attacks with the release of Tor 0.4.8.
no offense, but that's old news as of august of last year.
But yea this has been a big game changer for hidden services that were under constant DDoS, such as the Dread forum.