One of the huge issue on HN is lack of good algorithms for ranking. Currently all posts suffer from insufficient initial exposure to receive enough votes and thus false negatives are extremely high on HN. Just go to new page right now, take a look at most recent posting and you will find that <i>majority</i> of good genuine posts would never make it beyond their initial single upvote. Very small subset gets re-posted few times and only randomly some will get attention. Unfortunately papers are probably the biggest victim so you could have as well have collected all the links, did kind-of-random sort and you might still get fairly decent results. The bottom line is that never rely on HN's flawed ranking. Use that as weak signal, combine with Reddit, citations, tweet counts etc if you want to work around vast sea of false negatives that HN currently is.