Backlinks and referring domains are two of the most quoted numbers in SEO. They sound similar but measure different things, and the difference matters when you compare sites or plan how to earn links. This guide explains both, what nofollow and other link attributes mean, and how to read a backlink report without being misled by big numbers.
This guide is WriterFlowLab's editorial advice. Descriptions of how Google treats links come from Google's own documentation, linked below. You can check any site with our free backlink checker.
What is a backlink?
A backlink is a link from a page on another website to a page on yours. If a blog post on example.org links to your guide, that is one backlink to your site. Search engines use links to discover pages, and links from other sites are widely seen as one of the signals that a page is useful or trusted.
What is a referring domain?
A referring domain is a website that links to you at least once. If example.org links to you 50 times from 50 different pages, that is 50 backlinks but only one referring domain.
That is why referring domains are usually the more meaningful number. A thousand backlinks from a single site (for example, a link in a sitewide footer) is very different from a thousand backlinks spread across hundreds of independent websites.
Backlinks vs referring domains at a glance
- Backlinks count individual links. They can be inflated by sitewide links, comment sections and repeated mentions.
- Referring domains count distinct linking websites. They better reflect how many independent sources link to you.
- Referring pages, shown by some tools, count the distinct pages that contain at least one link to you.
Nofollow, sponsored and UGC links
Website owners can add a rel attribute to a link to tell search engines more about it. Google's documentation on qualifying outbound links describes three values:
- rel="sponsored" for links that are advertisements or paid placements.
- rel="ugc" for links in user-generated content, such as comments and forum posts.
- rel="nofollow" when the other values don't apply and the site would rather Google not associate it with the linked page.
Google says links marked with these attributes will generally not be followed. Backlink tools count them, so a profile with many nofollow links may contribute less to search visibility than the raw totals suggest. Links without any of these attributes are often called "dofollow" links.
Links to avoid
Google's spam policies define link spam as creating links to or from a site primarily to manipulate search rankings. Examples include buying or selling links for ranking purposes, excessive link exchanges, and using automated programs to create links. Google notes that paid links are fine when they are qualified with rel="nofollow" or rel="sponsored".
The safest long-term approach is to earn links by publishing things people want to reference: original data, useful tools, clear guides and helpful resources.
How to read a backlink report
- Start with referring domains, not the backlink total.
- Look at who links. Links from relevant, reputable sites in your field matter more than links from unrelated or low-quality sites.
- Check the anchor text. Anchor text is the clickable text of a link. Natural profiles usually include a mix of brand names, page titles, bare URLs and descriptive phrases.
- Note the nofollow share to understand how many links are qualified.
- Look for broken backlinks. Links pointing to pages that no longer exist can often be recovered with a redirect to the most relevant live page.
About link scores
Many SEO tools produce their own link-based score for a domain or page. These are proprietary metrics, calculated differently by each company, and none of them is a Google metric. In our backlink checker this is shown as DataForSEO Rank, DataForSEO's own score on a 0–1000 scale. It is not Moz Domain Authority or any other company's metric.
Why backlink numbers differ between tools
No tool sees every link on the web. Each provider runs its own crawler and keeps its own index, so totals for the same site can differ a lot between tools. Compare sites using the same tool, and treat the numbers as indicators rather than exact counts.
How to use this in your content work
- Benchmark: compare your referring domains with the sites ranking for your target keywords, using the keyword difficulty checker's top 10 averages.
- Learn from competitors: check which of a competitor's pages attract links, then consider what you could create that deserves links too. See how to find your competitors' keywords.
- Fix what you have: recover broken backlinks and make sure linked pages still work, using the SEO site audit.
Next steps
Check your own site in the backlink checker and note your referring domains, top linking sites and most common anchor text. Then compare one competitor the same way.
Sources
- Google Search Central: Qualify your outbound links to Google.
- Google Search Central: Spam policies for Google web search.
- DataForSEO API documentation: Backlinks Summary.