What Referring domain means
A referring domain is a distinct website that links to you at least once. Ten links from one site count as one referring domain, not ten.
A founder proud of a hundred backlinks might realize, after checking referring domains, that ninety of them come from just two sites repeatedly linking to different pages — much less diverse than the raw number first suggested.
A high referring domain count is not automatically better than a smaller number of higher-quality domains. One link from a site your buyers actually trust can matter more than ten from unrelated forums.
Check your referring domain count instead of your total backlink count when judging how diverse and broad your link profile really is.
Why this matters for builders
Track unique sites that link to you, not only raw backlink counts.
Mistake builders make often
Builders sometimes celebrate a rising backlink count without noticing most of the growth comes from just one or two sites, not from a genuinely wider set of domains.
What to do now
Read How to increase Domain Rating to focus on adding new referring domains, not just more links from existing ones.