Definition
Plain language
A score search engines use to guess how trustworthy a whole website is.
As stated in the literature
A site-level reputation signal used in ranking, derived from link graphs and other trust heuristics; applied as a prior over retrieved documents independent of per-document relevance.
Why it matters: It is a cheap way to filter out junk at scale, but it also means trust is granted to a whole site rather than checked page by page.
For example, a page on a long-established university site may be ranked above an identical page on a week-old blog purely because of the site it sits on.
Heard on the show
“Real search stacks have deduplication, freshness weighting, domain authority, maybe explicit AI-content handling, and the authors say straight out they don't know how those systems work.”Episode 248 — One Self-Written Page Is Enough to Collapse an AI Search Answer