Indeed. I didn't go into this level of detail, but this would clearly be a different problem than what we have on HN, where downvoting enforces norms across the

Indeed. I didn't go into this level of detail, but this would clearly be a different problem than what we have on HN, where downvoting enforces norms across the whole community. Twitter is exactly as you said, a group of (overlapping) communities sharing a platform. We all see the same comments on HN, but on Twitter everyone has their own feed. Downvoting on Twitter would need to have very different characteristics for the reasons you mention. On the other hand, you actually do need users to moderate other users if you want to maintain a civil community. The alternatives are heavy moderation, which doesn't scale and introduces an institutional bias, or a free-for-all, where emotion drowns out thought, which is roughly where Twitter is today. I absolutely agree the social graph should be leveraged. What if downvotes only by people you follow affect your feed? You already see retweets only from people you follow, so the idea that your followees influence what you see is part of the platform today. This just extends that influence into the negative direction. Posters absolutely need to see the downvotes they are getting, the point of the feature is to moderate behavior, not just to create a filter bubble. Obviously it's not a trivial issue and rolling out new features at Twitter's scale isn't easy either. However I'm pretty confident, with all the engineering talent they have, they could make progress if it was actually a priority.