Interesting and surely useful, but it has a ways to go yet. I think that their nod to defense against sockpuppeting is going to become increasingly necessary to platforms/systems whose main purpose is anonymous discussion.

Any difficulties in scaling will be a major obstacle to mainstreamization of this technology, as others have mentioned.

On the one hand, I am glad that people are working on tools like this, but on the other hand, it seems to silently reiterate the elephant in the room: our government fights against us. The public is still a bit behind in the information technology arms race.