What is Domain Authority ?
A score from 1-100 that predicts how a site will rank on search engines. Based on the principle that a higher ranking score will lead to a greater ability to rank on search engines, Moz developed this score. When comparing websites, Domain Authority is often used to establish a score based on several rankings and factors. Some websites have more Domain authority because their external links are of higher quality. Domain Authority is derived from a single DA score that considers various elements, including the number of root domains linking to the site and the overall number of connections. A website’s "ranking strength" can then be tracked over time using this number. Google does not consider Domain Authority to be ranking criteria, and as a result, it has no impact on search engine results.
DA relies on machine learning calculations, so if more, fewer, or different data points become available and are incorporated into those calculations, your site’s DA score may fluctuate. For example, if facebook.com were to acquire a billion new links, the DA of every other site would decrease compared to Facebook’s. The larger link profiles of more established and authoritative sites like Facebook take up more high-DA spaces, leaving less place for domains with weaker link profiles at the top end of the scale. Therefore, increasing your score from 20 to 30 is far easier than increasing your 70 to 80 points. Thus, Domain Authority should be used as a comparative statistic rather than an absolute metric for this reason. Moz’s Link Explorer, the MozBar (a free SEO toolbar from Moz), or the SERP Analysis portion of Keyword Explorer can all be used to determine a website’s Domain Authority.
All Moz Pro campaigns, the Moz API, and a slew of SEO and online marketing services use Domain Authority metrics. Sites with a significant number of high-quality external links (such as wikipedia.com or google.com) tend to have higher Domain Authority scores than smaller firms and websites with fewer inbound links. Domain Authority starts at one for every new website and increases over time as the site accumulates authoritative backlinks. Domain Authority predicts Domain Authority expects the potential of a place to rank in its particular competitive landscape; therefore, choosing your target DA should not be done randomly. Look at the DA rankings of the sites that directly compete with yours in the SERPs and try to outperform them.
When analyzing the areas in your target SERPs that may have stronger link profiles than you do – your genuine competitors — employ DA as a comparative statistic. A domain’s Domain Authority score is only "good," "average," or "poor" in the context of the competitive environment. This is because the measure is relative. There is no such thing as an absolutely "excellent" or "average" Domain Authority score.