
Competitive vector analysis: map your competitors’ semantic territory
Compare sites by meaning, identify semantic overlap and find territories competitors have not covered.
highlights
- • Keyword gap and embedding gap answer different questions.
- • Sites can compete thematically without sharing exact queries.
- • Paragraph-level analysis reveals the specific section winning a topic.
- • Low overlap is only an opportunity when demand exists.
- • A site centroid summarizes its thematic direction.
the limit of traditional keyword gaps
Keyword gaps show terms one domain ranks for and another does not. They are valuable, but they miss different language used to cover the same need and emerging topics with little keyword history.
They can also exaggerate differences when two sites describe the same concept with different vocabulary. Semantic comparison asks a second question: where do the domains overlap in meaning, regardless of the exact terms each one ranks for?
comparing sites with vectors
Create embeddings for comparable pages or sections, then find nearest neighbors across domains. The resulting map shows strong overlap, unique coverage and areas where one site provides more depth.
A typical workflow crawls each domain, extracts the primary content and records the closest competitor match for every page. Paragraph-level embeddings can then reveal the exact section where one competitor provides a stronger answer.
acting on overlap data
High overlap can reveal direct competitors and pages that need a stronger angle. Low overlap can reveal whitespace, but it must be validated with demand, audience fit and commercial relevance.
Pages that closely match several competitors while underperforming deserve a depth and quality review. Conversely, uncovered territory should become a content opportunity only after Search Console, market and audience data confirm that somebody needs it.
competitive centroids
A centroid is the average vector for a set of pages. Comparing centroids gives a high-level view of where each domain sits semantically and how its editorial direction changes over time.
The page closest to a centroid is often the most representative of the domain or cluster. Comparing those representative pages provides a compact view of how each competitor frames the market.
performance and scale
At larger scale, use approximate nearest-neighbor search instead of comparing every possible pair. Clean extraction and consistent chunking usually matter more than small model differences.
Two sites with 5,000 pages create 25 million pairwise comparisons, so sampling or a vector index becomes important. For exploratory work, a representative set can expose the main patterns before the process is expanded.
final thoughts
Semantic competitive analysis complements ranking and keyword data. Together they show both what users search for and how each site organizes knowledge around those needs.
The shift is from asking only who ranks for a phrase to asking who covers a territory of meaning most completely. That broader view produces better benchmarks and more defensible editorial priorities.
sources and further reading

Lucas Cassapula
Partner & Head of SEO at Wesearch and Co-founder of Mentionflow
I am a partner at Wesearch and co-founder of Mentionflow. I have worked with SEO for almost 10 years. I am a data-driven geek who is always testing hypotheses, looking for patterns and turning ideas into products. I share studies, experiments and automations focused on SEO and GEO.