How heat is calculated
Heat is a published formula, not an editorial grade. Missing metrics add nothing and are never estimated. Source figures are the last values fetched from a public API or page, at . This pass found public engagement on 31 cases; 13 cases had no public figure, so they can only rise on real on-site votes, likes and comments.
- Source-platform engagement (55%). Each figure is log(1+x), then weighted as below, then turned into a percentile within the same platform so YouTube view counts are not compared raw with X likes. That percentile is then multiplied by 1−e^(−raw/3), so a first-place item with only a little engagement cannot tie a high-engagement item on another platform. If a field cannot be fetched it is dropped and the remaining weights are rescaled.
- X: likes 35%, reposts 40%, views 25%
- YouTube: views 65%, likes 35%
- Reddit: upvotes 60%, comments 40% (no Reddit items in the catalog yet)
- GitHub repositories: stars 100% (pull requests do not borrow the repository’s star count)
- Hacker News: score 70%, comments 30% (the current HN items are comments without a public score, so they are omitted)
- On-site engagement from real visitors (45%). Rank-up votes 60%, likes 25%, comments 15%, also log(1+x). QA visits (?qa=1), the no-track cookie, crawlers, and WARP or our own traffic are excluded from public counts. One vote per visitor per case (a hash of cookie and IP), and a vote can be withdrawn.
- Recency decay. Half-life is measured from the source’s published date: 18 hours on the Today board, 4 days on This week, 14 days on All-time. On-site counts for Today and This week only include the last 24 hours or 7 days (UTC).
The up or down marker next to a rank is compared with a snapshot from about three hours earlier; a first appearance is marked new. This is not an official chart, and it is not a test of model quality.
