Hierarchical Clustering
Semantic ClusteringHierarchical Clustering is an algorithm that creates a tree (dendrogram) of cluster relationships, showing how subclusters merge into larger groups at successive levels. In SEO, it's used to build site category hierarchies—the dendrogram maps directly to navigation structure: main branches = categories, sub-branches = subcategories, leaves = articles. Unlike K-means (flat division into k groups), hierarchical clustering provides multi-level structure without needing to specify k upfront.
Hierarchical clustering complements K-means—K-means gives clusters, the dendrogram shows how those clusters connect to each other.
In practice, visualize the dendrogram and cut it at the level matching your site's navigation depth (2-3 levels for typical blogs, 4-5 for e-commerce).