Domain Authority measures a website's overall strength and predicted ranking ability on a 0–100 logarithmic scale. Moz created DA by analyzing their link index and using machine learning to identify patterns that correlate with actual Google rankings. The score gets harder to improve as you climb—jumping from 20 to 30 is much easier than 70 to 80. DA primarily weighs your backlink profile: how many domains link to you, the authority of those linking domains, and the quality of individual links. It also factors in technical elements like site structure and indexability, though backlinks drive most of the variation. A site with 50 quality referring domains from established publishers will score higher than one with 500 links from blog comment spam. Important distinctions: DA is predictive, not prescriptive. Google doesn't use it in their algorithm. They have their own internal metrics we'll never see. DA exists to give SEOs a shorthand for comparing sites and tracking relative progress. When we evaluate link prospects at Ottawa SEO, we check DA alongside actual traffic, topical relevance, and link placement context. A DA 35 niche blog with engaged readers often beats a DA 50 content farm. The score updates roughly monthly as Moz recrawls the web. Your DA can drop even if you're doing everything right, simply because competitors gained stronger links. That's the logarithmic nature—everyone's fighting for the same ranking space. We've seen Canadian e-commerce sites sit at DA 25–35 and dominate local search, while DA 60+ sites struggle in competitive niches because they lack topical authority or have poor on-page optimization. Treat DA as one data point among many. It's useful for quickly sizing up link opportunities or tracking whether your link building moves the needle over quarters, but obsessing over the number itself misses the point. Focus on acquiring links that actually drive referral traffic and topical authority. The DA score will follow if you're building a legitimate backlink profile.