Ever since google killed sharing within google reader itself (they meshed it into Google+) there is no way for 1st tier content junkies (i.e. people who have a ton of RSS feeds) to share good reads with each other. Twitter has horrible S/N, no one is on Google+ and if they were it would have same problem as twitter. Sharing within Google Reader was perfect b/c the majority of people who used Reader were other content junkies. HN does this but only for 50 stories a day and isn't curated from content junkies with my shared interests.