Link Intelligence & Curation · Essay № 04
How SignalScore Works.
A long-form essay on the formula behind the only link database that refuses to recycle the same DR-90 list your competitors are already pitching. What follows is the methodology, the math, and the editorial QA — written for the senior SEO who plans to audit every line of it.
§ 01 — The Premise
A single comparable number, built from four honest signals.
SignalScore is a 0–100 composite that ranks every indexed URL by how useful it is as an outbound link target for editorial content. It collapses four signal categories — Domain Authority, Topical Relevance, Editorial Standards, and Outbound-Link Velocity — into one number that holds up across niches, languages, and content formats.
We did not invent SignalScore to chase a leaderboard. We invented it because the legacy link databases kept giving us the same DR-90 domains — half of which fail a five-minute editorial sniff test — and we needed a way to surface the long tail of genuinely linkable URLs that nobody else was surfacing. Today, the median SignalScore on our index is 41 and the 90th percentile is 68. Anything north of 80 is, in our experience, where the pitchable inventory lives.
The rest of this essay opens the formula, walks through each of the four signals in turn, shows the curation math that filters the index from 41 million pages down to the 1.4% of URLs we treat as link-worthy, and ends with the benchmark numbers a procurement lead will want before signing off on a trial.
§ 02 — The Four Signals
The ingredients, individually inspectable.
We expose every weighted input so a senior SEO can audit SignalScore rather than take it on faith. Click any chapter number to inspect the measurement.
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01
Domain Authority
Weight: 30%
A Moz-DA-style estimate computed on the live editorial link graph, refreshed every 15 minutes from 2.3 billion outbound links. We do not use a third-party DA score as a black-box input — we recompute the underlying link graph ourselves so that freshly-launched authoritative outlets (think a new Substack from a former NYT editor) earn authority within hours, not quarterly crawls.
DA is necessary but not sufficient. A domain can score 92 and still be a junk farm — which is why DA is capped at 30% of the final SignalScore.
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02
Topical Relevance
Weight: 30%
A semantic vector match between the prospective linking page and the target URL, computed against a 12,000-label topic taxonomy. The signal rewards topical alignment over raw authority: a DA-55 niche site that publishes exclusively about climate-tech will outrank a DA-90 generalist when your article is about grid-scale battery storage.
Measured with a fine-tuned embedding model trained on 4.1 million editorially-vetted (source, target) pairs.
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03
Editorial Standards
Weight: 25%
A binary editorial-quality filter applied to every URL in the index. We score 14 checks including: byline presence, corrections policy, fact-checking disclosure, ad-to-content ratio, syndication patterns, AI-generated content markers, and historical accuracy audits. URLs that fail any hard check are removed from the index entirely; URLs that pass are scored on a 0–100 softness scale.
This is the signal that disqualifies 74% of "high-DR" domains surfaced by legacy link tools.
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04
Outbound-Link Velocity
Weight: 15%
The rate at which a domain acquires new inbound links from other editorial pages, normalized against its publishing cadence. High velocity on a publishing-light site is a strong proxy for "people are citing this because it earned the citation" — and is the single most predictive feature we have for linkability that traditional DA misses.
Measured over a rolling 30-day window, refreshed every 15 minutes.
SignalScore = 0.30·DA + 0.30·Topical + 0.25·Editorial + 0.15·Velocity
§ 03 — The Curation Math
From 41 million pages down to the 1.4% worth linking to.
We get asked the same question in every procurement call: "If your index is so curated, why is it so big?" The answer is that size is upstream of curation — you cannot filter 2.3 billion outbound links down to a useful list unless you've already indexed everything.
| Stage | Filter | Pages in | Pages out | Pass rate |
|---|---|---|---|---|
| Crawl | Editorial pages discovered via 41M seed domains | 41,000,000 | 41,000,000 | 100% |
| Editorial Standards | 14 hard checks (byline, corrections, AI markers, ad ratio…) | 41,000,000 | 10,620,000 | 25.9% |
| Domain Authority Floor | DA ≥ 25 on the live graph | 10,620,000 | 3,180,000 | 29.9% |
| Topical Coverage | Mapped to at least one of 12,000 topic labels | 3,180,000 | 2,140,000 | 67.3% |
| Velocity Sanity | Outbound velocity within 4σ of domain baseline | 2,140,000 | 574,000 | 26.8% |
| Pitchable index | SignalScore ≥ 60, last refreshed ≤ 15 min ago | 574,000 | 574,000 | 1.4% of crawl |
Of the 41 million editorial pages we crawl, 574,000 survive every filter and become part of the pitchable index you query through the app. That is the 1.4%. Every page you see in a saved list has cleared all five stages in the last 15 minutes.
§ 04 — Freshness & Editorial QA
The infrastructure layer competitors can't easily copy.
Refresh cadence
The full 2.3-billion-link graph is re-scored every fifteen minutes. New outbound links are absorbed within the same window — not on the next weekly crawl.
"High-DR" domains that fail our editorial check
When we benchmarked our top-10,000 DR-90 domains against our own editorial-standards filter, 74% were disqualified — the same domains the legacy tools are still happily recommending.
Human editorial QA passes
Three times a week, a senior editor audits random samples of the index and the surfaced lists. Failed samples trigger a model retraining and a one-hour suppression window while we patch the underlying issue.
§ 05 — Independent Benchmark
Side by side, claim to claim.
We do not editorialise about competitors — that is not what this page is for. Below is the same benchmarking table we hand to procurement leads who ask "how is this different from the link tool we already pay for?" Numbers are from an independent benchmark conducted Q1 2025 on a 1,000-keyword SaaS link-prospecting workload.
| Capability | NDAGLinks | Legacy DR tools avg of 2 incumbents |
Δ |
|---|---|---|---|
| Time-to-pitchable-list (1,000 prospects) | 4 min 12 sec | 3 hr 48 min | −98.2% |
| Index refresh cadence | 15 min | 7 days | ~670× |
| Built-in editorial-quality scoring | Yes — 14 hard checks | No | — |
| "High-DR" domains passing editorial standards | 26% | ~3% | ~9× |
| Customer NPS (Q1 2025) | 71 | ~34 (industry avg) | +37 pts |
| Average time saved per session | 3 hr 12 min | n/a | — |
Benchmark conducted independently by the European Search Awards judging panel, Q1 2025, on a 1,000-keyword SaaS link-prospecting workload. Full PDF available on request to enterprise evaluators.
End of essay
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