Every site page carries an authority score out of 100. It is a link-graph measure of how established the site is on the open web — here is what it is built from and how to read it.
The score is sourced from Open PageRank, which derives it from the Common Crawl host graph — the public record of which websites link to which. We display it on a 0–100 scale, alongside the site's global rank and its count of referring domains, so the one number always sits next to the evidence behind it.
A link-graph score is the right tool here because it measures the same thing an advertiser cares about: whether the wider web treats this site as worth pointing at. It cannot be bought with traffic spikes, and it moves slowly — which is what you want from a number used to compare sites.
Scores compare best within a niche. A 40 in a small hobby niche can be a leading site; a 40 in mainstream news is mid-table. That is why every site page lists similar sites — same niche, closest authority — as the honest comparison set, and why network pages show the authority spread of their book rather than a single average.
Unranked is not zero. A site the link graph has never seen shows no score at all; a site ranked at the bottom shows a low one. The distinction matters at the long tail, where most of the web lives.
It is not a traffic estimate, not a quality verdict on the content, and not a ranking factor we invented — it is an independent, reproducible measure from public crawl data. Use it the way a network's own sales team would: as one input beside the niche, the evidence of who monetises the site today, and the verification labels.