Significant — the news feed with a p-value

Methodology

Significant watches 15 public topic feeds on the open social web (Mastodon + Bluesky + RSS, via the Surf API) and admits a story to the feed only when the discussion burst is statistically significant against that feed's own history.

1. Exposure is posts, not time

Feeds run at wildly different speeds (politics ≈ 4 posts/day, news ≈ 3,400/day). So each term's burst is measured as a proportion of posts: it appeared in x of the last n posts, against a baseline proportion p₀ estimated from everything older (Laplace-smoothed). Both feeds face the same gate.

2. Exact binomial test

p = P(X ≥ x) where X ~ Binomial(n, p₀)
z = (x − n·p₀ − ½) / √(n·p₀(1−p₀))

Computed exactly (log-gamma), not approximated, for every window size we actually see.

3. Bonferroni correction — the honest part

Every cycle tests thousands of terms across all topics. Testing many hypotheses and reporting the best one is how junk science — and every trending-topics algorithm — works. So the gate is corrected for every term we looked at:

pass ⇔ p < α / m, α = 0.01, m = all terms tested this cycle

3½. Velocity anomalies

Separately from term bursts, each topic's posting rate is tested: posts in the last hour vs. a Poisson expectation from that feed's own same-UTC-hour history (diurnal-corrected, ≥48 h of history required). These tests count toward m and face the same corrected gate — they catch "something is happening" before we know what.

4. Structural gates

A term must also appear in ≥ 4 posts from ≥ 3 distinct authors. One loud account is not news. Topics without ≥ 30 baseline posts spanning ≥ 3 h are marked calibrating and not tested at all.

5. What the AI does and doesn't do

Claude writes the one-line neutral headline for events after they pass the gate (one batched call, cached forever). The statistics contain no AI. If no key is set, deterministic template headlines are used — the feed is identical.

Honest limitations

Baselines deepen over days; a freshly-booted instance is under-calibrated and says so per topic.
Presence/absence per post ignores term burstiness within authors' posting habits — the author gate is a crude proxy.
Bonferroni is conservative by design. We will miss real events. We prefer that to lying to you.