http://www.righto.com/2013/11/how-hacker-news-ranking-really-works.html http://www.righto.com/2013/11/how-hacker-news-ranking-really... You might expect that e

http://www.righto.com/2013/11/how-hacker-news-ranking-really-works.html http://www.righto.com/2013/11/how-hacker-news-ranking-really... You might expect that every time you visit Hacker News, the stories are scored by the above formula and sorted to determine their rankings. But for efficiency, stories are individually reranked only occasionally. When a story is upvoted, it is reranked and moved up or down the list to its appropriate spot, leaving the other stories unchanged. Thus, the amount of reranking is significantly reduced. There is, however, the possibility that a story stops getting votes and ends up stuck in a high position. To avoid this, every 30 seconds one of the top 50 stories is randomly selected and reranked. The consequence is that a story may be "wrongly" ranked for many minutes if it isn't getting votes. In addition, pages can be cached for 90 seconds.