An H1 tag is the top-level HTML heading element (<h1>) that typically contains the primary topic or title of a webpage. Search engines treat it as a strong relevance signal, not a ranking guarantee, but it directly influences how Google interprets page content and whether your page matches user intent. Every page should have exactly one H1 that clearly describes what the content delivers. Multiple H1s used to be debated, but modern HTML5 allows them in sectioned content—still, one focused H1 remains best practice for clarity and SEO. The H1 doesn't need to match your title tag verbatim, but both should target the same core keyword or intent. We often make the H1 slightly more descriptive or user-friendly than the title tag, which has character limits and click-through optimization concerns. H1s matter because they anchor your content hierarchy. Google's algorithms, especially after passage ranking and MUM updates, parse heading structure to understand topic flow. A vague H1 like "Welcome" wastes a major relevance signal. A specific H1 like "Ottawa Commercial Roof Repair – Emergency & Scheduled Service" tells crawlers and users exactly what you offer and where. Common mistakes include leaving the H1 identical to the site logo, stuffing keywords awkwardly, or skipping it entirely on key landing pages. In our audits across 500+ domains, we routinely find e-commerce category pages with auto-generated H1s like "Category Archive: Products" instead of "Men's Winter Jackets Canada – Insulated & Waterproof Options." That's a missed opportunity. H1s also affect accessibility. Screen readers use heading hierarchy to navigate content, so a proper H1 improves usability for visually impaired users, indirectly supporting engagement metrics Google monitors. When we redesign client sites, we map H1s during wireframing, ensuring each template—homepage, service page, blog post—has a clear H1 strategy. It's not a magic lever, but ignoring H1 structure is leaving easy optimization wins on the table.