LinksLinking root domainsRDs

Referring domains

The number of unique domains linking to a site or page, generally a more meaningful measure of link popularity than raw backlink count.

In full

One thousand links from one domain represent roughly one endorsement; one thousand links from one thousand domains represent a thousand. Diversity of referring domains (across types, topics, countries and authority levels) is what a natural profile looks like. Counting is index-dependent, so numbers vary considerably between backlink tools, and comparisons should stay within one vendor.

Example

A campaign yields 90 links from 12 domains via syndication, so the referring-domain count barely moves despite the headline number.

Related terms

Backlink

A hyperlink from one website to another, historically the strongest external signal search engines use to judge a page's importance and…

Link profile

The aggregate characteristics of all links pointing to a site: source diversity, anchor text distribution, follow ratio, topical relevance…

Third-party authority metrics

Vendor-calculated 0-100 scores estimating a domain's link strength (Ahrefs DR, Moz DA, Semrush Authority Score, Majestic Trust Flow) none…

Digital PR

Earning editorial coverage and links from media outlets through newsworthy assets (original data, expert commentary, campaigns) rather…

Link graph

The network of all pages as nodes and hyperlinks as edges, over which link-based ranking algorithms such as PageRank are computed.

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