Not sure why the HN submission didn't link to the original post: http://www.righto.com/2013/11/how-hacker-news-ranking-really...
Discussion here: https://news.ycombinator.com/item?id=6755071
Discussion here: https://news.ycombinator.com/item?id=6755071
It's not a duplicate (as far as HN is concerned), the URLs are slightly different.