OpenBrief
⌘K
Log in Sign up
What the picker changes
  • Top topics digest — the cards score the selected period against the prior 4 weeks.
  • 12-week heatmap & outlet matrix — show the 12 weeks ending at the selected week (they slide back with the picker, they aren’t a fixed snapshot).
  • Per-topic volume / alias drift — same 12-week trailing window, anchored on the selected period.
  • Coverage gap quadrant — scores the selected period against the 12 weeks before it (not including it).
  • Anomaly cards — only show alerts the detector fired during the selected period. Quiet weeks legitimately show none.
What stays as-is
  • Outlet orientation strip / lean colours — context-only, drawn from the last 12 weeks of activity regardless.
  • Co-occurrence graph — recent-activity anchored, not picker-driven.
  • Source & topic profiles — all-time data for the topic; the picker doesn’t affect them.
Rolling 7 days is a sliding live window for “current vibes”; switch to Weekly to compare specific weeks side-by-side.
Weekly Rolling 7 days
live window
Topic · social

Tunnel Ventilation Systems

1 post · 45 engagement · first seen 31 May 2026 · last seen 31 May 2026

The Auckland City Rail Link is conducting extensive real-life safety tests, including fire drills, tunnel evacuations, and emergency scenarios with unruly passengers and prams, to ensure system readiness before its official opening.

Platform mix

Where the conversation is happening. Engagement is volume-weighted (likes + 2×shares + 3×replies); a small number of high-impact posts can outrank a high-volume but low-engagement platform.

  • reddit
    1 post · 45 engagement
    45

Top posts by engagement

The most-engaged posts referencing this topic. Engagement is likes + 2×shares + 3×replies; the order matches the digest ranking on /social.