Feature request for the submit page: live AI fuzzy suggestions of URLs to prevent dupe submits.
People post links to past discussions are not because they're bad (look at all those reposts!) but because they're good (wow, interesting comments from the past!) - at least in the best case.
Because there's so much randomness in what gets noticed on /newest, overzealous dupe detection would prevent many good articles from ever getting discussed. That would be a poor trade for better deduplication! HN's dupe detector is therefore left porous on purpose (https://hn.algolia.com/?dateRange=all&page=0&prefix=true&que...), so good stories get multiple chances to get attention. We will probably implement karma sharing amongst the various submitters of an article, though, at least when it's a first-time discussion.