A backlink is a single link, counted individually. A referring domain is a unique website that links to you at least once — one referring domain might account for one backlink, or fifty.
Why the distinction matters
Ten backlinks from ten different sites is a very different signal than ten backlinks from the same site linking to you repeatedly. The first looks like genuine, distributed interest. The second is often just one relationship — useful, but not the same kind of vote of confidence.
This is why SEO tools report both metrics separately, and why referring domain count is usually the more meaningful number to track over time. A jump in backlinks with a flat referring-domain count often just means one site linked to you from several pages.
What to actually track
- Referring domain count, as your primary trendline
- The relevance and quality of each new referring domain, not just the count
- Backlink count as a secondary detail — useful, but easy to inflate artificially
Our Free Backlink Sites List is organized around distinct sites for exactly this reason — it’s a list of referring-domain opportunities, not a count-padding exercise.