How Hacker News ranking works: scoring, controversy, and penalties (2013)

Hacker News uses a published ranking formula based on upvotes, submission time, and a "gravity" exponent, but analysis of top stories reveals that approximately 20% of front-page articles are subject to invisible penalties that significantly alter their rankings. Stories tagged with "NSA" are systematically penalized, and articles marked as "controversial" receive severe penalties after reaching 40 comments, though the platform no longer applies NSA-specific penalties as of the article's edit note. The ranking system reranks stories only when they receive votes or randomly every 30 seconds for the top 50 stories, which can result in temporarily incorrect rankings.