What Are Backlinks?
Backlinks — also called inbound links or external links — are hyperlinks on one website that point to a page on another website. When Site A links to Site B, that link is a backlink for Site B. Backlinks are the foundational mechanism through which search engines determine the relative importance and credibility of web pages. A page with many high-quality backlinks pointing to it is, by this logic, more important and authoritative than a page with few.
Google's founders Larry Page and Sergey Brin formalized this principle in their original 1998 PageRank paper, which treated the web as a citation network analogous to academic publishing — where papers (pages) that are cited by more respected sources (high-authority sites) deserve more prominence. Three decades later, the principle is still fundamental. Google has confirmed backlinks as one of its top three ranking factors.
Not all backlinks are equal. A backlink's value is determined by the authority of the linking domain (higher DA = more value transferred), the relevance of the linking page's topic to the linked page's topic, the placement of the link (editorial body text vs footer vs sidebar), and the link's attribute (followed links pass authority; nofollowed links generally do not). A single editorial link from a relevant, high-authority publication can outperform hundreds of directory or forum links.
Why Backlinks Matter for Marketers
Backlinks are the primary determinant of whether a domain can compete for competitive keywords. Content quality, technical optimization, and user experience all matter — but in competitive categories, the sites that rank are almost universally those with the most authoritative backlink profiles. This is documented consistently in industry correlation studies: referring domain count is the single metric most correlated with ranking position across topics.
The asymmetry of backlink value means that link acquisition quality matters more than quantity. Pursuing volume of links from low-quality sources creates a diluted profile that may not improve rankings and can, if the links are sufficiently spammy, attract manual or algorithmic penalties from Google's spam detection systems. A focused strategy of earning 10–20 high-quality links per month from relevant, authoritative sites will outperform 100 low-quality links in both ranking impact and sustainability.
Backlinks also have direct referral value independent of SEO. A link from a high-traffic publication or an industry resource page sends qualified visitors — people already in context and potentially interested in your offer. For some B2B brands, referral traffic from a few strategic backlinks in relevant publications can be a meaningful direct traffic source.
How to Implement Backlink Acquisition
- Publish linkable assets: Original research, comprehensive guides, data visualizations, and tools are the content types most likely to earn organic backlinks from journalists, bloggers, and researchers. Invest in one high-quality linkable asset per quarter.
- Digital PR: Pitch story angles using proprietary data or expert perspective to journalists at publications your audience reads. Editorial backlinks from credible outlets carry significant authority weight.
- Outreach-based link building: Use Ahrefs or Semrush to identify sites linking to competitors and similar content. Reach out with a clear value proposition — your content as a resource replacement, a contribution, or a complementary reference.
- Guest contributions: Byline articles on industry publications with contextual links to relevant pages. Focus on publications with genuine editorial standards and real audiences.
- Monitor and reclaim lost links: Ahrefs alerts can notify you when existing backlinks are lost (linked page removed, redirect changed). Reach out to reclaim links to broken pages by providing the updated URL.
How to Measure Backlinks
Primary metrics: number of referring domains (unique sites linking to you), Domain Rating or Domain Authority trend, and the authority distribution of linking domains (what percentage come from high-DA sites). Track these in Ahrefs Site Explorer or Semrush Backlink Analytics monthly.
Set acquisition targets by category competitiveness — if competing pages average 300 referring domains and you have 80, that's the gap to close. Track new referring domains gained per month as a velocity metric and measure link quality by average DR/DA of new linking domains.
Backlinks and AI Search
Backlinks are the strongest predictor of how frequently a brand's content appears in AI training corpora and retrieval systems. Pages that have earned backlinks from authoritative sources are crawled more deeply, appear more frequently in datasets used to train large language models, and rank higher in the search indices AI retrieval systems query. When Perplexity, ChatGPT, or Google AI Overviews select sources for generated answers, they disproportionately pull from content that is broadly linked to and well-ranked. Building a strong backlink profile is among the most durable investments a brand can make in both traditional SEO and long-term AI visibility.