Already Mark had set up Hubski without any “down votes”. Using the Hubwheel as a voting mechanism got rid of arrows altogether and thereby set up a way of giving only positive reinforcement on the site.
I'm still reading the interview, but this line caught my eye. Over my 516 days here, I've noticed a lot of disagreements -- but sites are also shared because of thoughtful disagreement. People care enough about a post to disagree with it. People very much want to share a post and their disagreement. This is much more sophisticated than up or down votes. .. ok, must read on.