Trust me, I had my regrets in noting this as a dupe, but HN's guideline is that unless there's "significant new information", submissions substantially similar in theme, regardless of whether they're the same or a different URL (within a year of a prior posting with significant discussion) get buried. See: <https://news.ycombinator.com/item?id=9716270>

A big part of the concern is duplicate discussions: <https://news.ycombinator.com/item?id=27028471>

I'll occasionally gather up related links when a large news story hits and post those to the first / main discussion.