Link building is off-page SEO. It's not just part of it—it's the foundation. Off-page SEO refers to any ranking signal that originates outside your website, and backlinks carry more weight than any other external factor in Google's algorithm. When authoritative sites link to yours, they're essentially vouching for your content's credibility, which Google interprets as a trust signal. Off-page SEO does include other elements like unlinked brand mentions, social media engagement, local citations (especially in Google Business Profile for local search), online reviews, and even podcast appearances or PR coverage. These contribute to your overall digital footprint and can indirectly influence rankings by driving traffic and building brand recognition. But none of these factors match the direct algorithmic impact of a quality backlink from a relevant, authoritative domain. The distinction matters because link building requires different skills than on-page optimization. On-page SEO is about what you control directly—your content, HTML structure, internal linking, and technical setup. Off-page SEO, particularly link building, requires outreach, relationship development, content marketing that earns natural links, or strategic partnerships. You're persuading external parties to reference your work. At Ottawa SEO, we see link building as roughly 40–60% of the SEO effort for competitive queries in markets like Ottawa, Toronto, or any niche with established players. The exact ratio depends on your baseline—if your technical SEO and content are weak, fix those first. But once your on-page foundation is solid, off-page link acquisition becomes the primary lever for climbing SERPs, especially for commercial keywords where everyone's content is reasonably competent. One caution: not all off-page activity is link building. Guest posting for links is link building. Getting mentioned in a Globe and Mail article without a link is off-page SEO but not link building. The terminology overlap confuses people, but functionally, if you're trying to improve rankings through external signals, you're doing off-page SEO, and links are your main tool.