Research

Each stem is one named security event; its height is that event's peak-month share of HN titles, all rising from the same 0% baseline.

✦ Insights Heartbleed reached 2.28% of titles in April 2014, with a peak share that rose from 0.

Named-event keywords are absent for years, then dominate in the exact month of disclosure. The absolute share is the signal — the from-zero z-score is degenerate.

Each row is a topic pair on a fixed −1 to +1 correlation axis. Hollow marks use monthly title-share levels; filled marks use month-to-month changes after first-difference detrending.

The line is average comments per story each year, plotted across the full census from 2007 on the left to 2017 on the right.

✦ Insights Comments per story increased significantly, rising from 3.2 in 2007 to 7.8 in 2017, demonstrating a 2.4-fold expansion.

Comment volume grew ~32× while stories grew ~13× across the census. Census-complete; the cultural-vs-UI cause is not established.

Each line tracks one depth bucket's yearly share of all comments — top-level versus replies nested four-plus deep; watch where they cross.

✦ Insights Top-level comments decreased from 48 percent in 2007 to 21 percent by 2018, while deep threads increased around 2015.

Climbing every comment’s parent chain to its story: top-level comments fell as depth-4+ replies grew, crossing ~2015. Census 2007–2018 (every comment); the cultural-vs-UI cause isn’t established.

Each bar is a comment-tree depth; its height is the share of comments at that depth that drew at least one reply, in the 2016 census.

✦ Insights Reply probability increased from 46.2 percent at depth 1 to 51.3 percent at depths of 10 beyond.

A reply is about as likely at depth 6 as at the top — even rising to 51% at depth 10+. Census 2016; this is why threads got so deep, and it means the never-replied comments are the short ones, not the deep ones.

Each line is a keyword's yearly share of HN titles — NSA and COVID — sitting near zero except for one sharp spike, then settling back.

• COVID — 3.4% of titles in 2020
• NSA — 1.2% in 2013 (the Snowden leaks)
• Ukraine — 1.1% in 2022 (the invasion)

✦ Insights COVID reached 3.4% of titles in 2020, marking the largest single-event spike observed.

The world surfaces sharply in the conversation, then fades — Snowden (2013), the pandemic (2020), the invasion of Ukraine (2022), all census-exact from the frozen 2007–2022 census. Ukraine's spike was held back until 2022 finished crawling — the thin early sample read 0.6%; the closed census says 1.1%, nearly double. We don't chart a number until we can stand behind it.

Each bar is a leaderboard size; its height is the share of census stories that land on both the points-ranked and comments-ranked top list at that size.

✦ Insights Only 26 of the top 100 stories by points also appear in the top 100 by comments. At the top 1,000, the overlap is 35 percent.

Ranking the census by points vs by comments gives near-different lists — 16–35% overlap across sizes — and 37 of the 100 most-discussed are Ask HN (mostly “Who is hiring”), though Ask HN is ~3.5% of posts. Discussion and approval are different axes.