5) cool! Didn't know about that. 4) fair enough "Lots of people (51 upvotes) didn't see the first one, so maybe it doesn't do any harm?" - It harms the peop

5) cool! Didn't know about that. 4) fair enough "Lots of people (51 upvotes) didn't see the first one, so maybe it doesn't do any harm?" - It harms the people who already read the story, and now have decreased signal:noise on their front page. - It helps the people who missed it the first time around who find it interesting. - It helps the people who already read the story, and who were interested in the HN discussion of the story (at http://news.ycombinator.com/item?id=360412 http://news.ycombinator.com/item?id=360412). These people now get an influx of new comments to think about. The last point only works because the user community pointed out the duplicate, and collectively decided that on-topic discussion (as opposed to this meta-ish discussion) best belonged under the original posting. Possible conclusion: dupes are okay (even net good) on a site with a principled user community. Probably net bad on a site with a more chaotic community. Feature idea for social news sites: let (high karma?) users fuse dupes' discussion pages into one.