The practice of linking from one page on your site to another. Internal links shape three things: how crawlers discover URLs, how PageRank flows through the site, and how users navigate. A common SEO pattern is to link from high-authority pages (homepage, popular posts) to pages you want to rank for specific terms, using descriptive anchor text. Pillar-and-cluster structures and breadcrumb trails are both internal-linking strategies. Unlike backlinks, you have full control over your internal linking — making it one of the easier SEO levers to pull and one of the most under-used.