Domain Authority (DA) is a proprietary scoring system initially developed by the web analytics and SEO firm, Moz. DA works by benchmarking a domain against its competitors to estimate its perceived relevance and its likelihood of appearing in search results for a given topic.
DA serves as a proxy for the perceived credibility of the information presented on a website. In other words, it is fundamentally a measure of a site’s reputation. DA illustrates how trustworthy a site’s content is when compared to the material on similar websites.
Although Moz pioneered the concept of DA, it is no longer the sole service that employs this type of measurement today. Many distinct SEO tools now incorporate some form of domain authority assessment.
While DA is not an official ranking factor for search engines like Google, it can provide website owners with a valuable approximation of how their domain is likely to perform and the degree of trust their audience places in them.