I am not a crypto guy, but my understanding is that users can downvote each other, and the more downvotes a user gets the harder the proof-of-work problem they had to solve before they post. If you received enough hate, your CPU would spike for a couple of minutes each time you tried to post, thus disincentivizing bad behavior.
I see on github the project is officially dead now:
https://weblog.masukomi.org/2018/03/25/zed-shaws-utu-saving-...
I am not a crypto guy, but my understanding is that users can downvote each other, and the more downvotes a user gets the harder the proof-of-work problem they had to solve before they post. If you received enough hate, your CPU would spike for a couple of minutes each time you tried to post, thus disincentivizing bad behavior.
I see on github the project is officially dead now:
https://github.com/zedshaw/utu