Domain Authority is a proprietary score created by Moz that attempts to predict ranking potential. It ranges from 1 to 100, with higher scores suggesting stronger ranking ability. The score is calculated using machine learning against Moz's link index, weighing factors like the number of linking root domains, total backlinks, and the authority of those linking sites. The critical thing to understand: Google does not use Domain Authority. It's not part of any search algorithm. DA is a correlation metric—sites with high DA tend to rank well because they have the underlying signals Google actually cares about (quality backlinks, content relevance, technical health), not because of the DA number itself. At Ottawa SEO, we track DA across our 500+ domain portfolio as a rough benchmark, but we never optimize for it directly. A site can jump from DA 25 to DA 40 by acquiring links from high-authority domains, but if those links are irrelevant or the content is thin, rankings won't follow. Conversely, a DA 15 local business site can outrank a DA 50 competitor for commercial keywords if it has better local signals, content relevance, and targeted backlinks. DA is logarithmic, meaning it gets exponentially harder to move up as you climb. Going from DA 20 to 30 might take dozens of decent backlinks; going from 70 to 80 could require hundreds of authoritative links. For most Canadian SMBs, a DA of 30–50 is realistic and sufficient if paired with strong topical authority and local optimization. Use DA as a comparative tool when evaluating link prospects—a backlink from a DA 60 industry site typically carries more weight than one from a DA 15 blog—but don't chase the number. Focus on earning links from relevant, trusted sources in your niche. That's what moves rankings, and DA will follow as a byproduct.