Referring domains vs. backlinks
If one blog links to your homepage from ten different articles, that's ten backlinks but one referring domain. A hundred backlinks from four different sites is a much narrower, more concentrated link profile than a hundred backlinks spread across sixty different sites — even though the raw backlink count looks identical.
Why the distinction matters
A link profile spread across many distinct, unrelated domains is generally a stronger and harder-to-fake trust signal than a large number of links concentrated on very few domains. Earning links from many different independent sites organically takes real relevance and outreach, while backlink count alone can be inflated cheaply by one cooperative site linking many times over — a sitewide footer or sidebar link, for example.
What to track instead of raw link count
When building out a domain inventory or reporting client progress, growth in new referring domains is usually the more meaningful number to watch than total backlinks, since it reflects how many genuinely different sites have chosen to link to the target — not how many times one site did.