Reading these answers reminded me why I love HN - actually thoughtful perspectives :) Guess a lot boils down to two variables - (a) suggestion UX quality and (b) definition of 'rejection' event. I skimmed through the paper and it turns out that 91% figure is based on feedback from 70 people and anonymous feedback wasn't allowed. So, 'overwhelming 91% favorable' can be paraphrased to `64 people out of the total 16k user base said they liked it'. Would be interesting to see indirect metrics like retention on day 15.