How to Use Semantic HTML5 Tags to Boost Your SEO

23 décembre 2023 00:00|SEO Technique|Temps de lecture : 5 min

When building a webpage, it's easy to rely on generic <div> and <span> tags for everything. They are the universal building blocks of layout. However, these tags are non-semantic; they tell the browser how to display content but say nothing about what that content is.

This is where semantic HTML5 tags come in. Tags like <header>, <main>, <article>, and <aside> act as signposts, giving search engines a clear map of your page's structure and helping them distinguish your core content from the surrounding noise.

Why Bother Telling Search Engines What's Important?

Modern search engines are incredibly smart, but the internet is a noisy place. A single webpage contains your main content, but also navigation menus, advertisements, related post links, and footer information.

Without a clear structure, a search engine might dilute the importance of your main topic by giving too much weight to this "boilerplate" content. Using semantic HTML allows you to take control of the narrative. Instead of letting the engine guess, you explicitly tell it: "Hey, this part is the main event. That part over there is just supporting material."

This simple act of clarification can have a significant impact. A case study on a high-traffic website showed that after re-engineering their page templates to use proper semantic HTML5 tags, organic traffic increased by approximately 30%.

Semantic HTML5 Tags Integration Results

This demonstrates that helping search engines understand your content more clearly can lead to tangible ranking improvements. In a SeoSpeedup Site Audit, one of the things our crawler checks for is a coherent page structure, as it's a foundational element of good technical SEO.

How to "Map Out" Your Page with Semantic Tags

Think of your webpage's structure in terms of a hierarchy. The goal is to separate the main, unique content of the page from the repetitive, site-wide elements.

Important Note: Semantic tags define meaning and structure, not visual appearance. All styling should be handled by CSS classes. You should be able to add or remove these tags without breaking your page's layout.

Step 1: Define the Major Regions with <header>, <main>, and <footer>

Almost every webpage can be divided into three logical parts:

  • <header>: Contains introductory content or navigational links for the entire site, such as the logo, primary menu, and search bar.
  • <main>: Contains the dominant, unique content of the document. There should only be one <main> element per page.
  • <footer>: Contains information for the section it's in, typically the whole page. This usually includes copyright information, links to related documents, and contact info.

Your basic HTML structure should look like this:

1<body>
2     <header>
3          <!-- Site-wide header content, often including a <nav> element -->
4     </header>
5
6     <main>
7          <!-- The unique, core content of this specific page -->
8     </main>
9
10     <footer>
11          <!-- Site-wide footer content -->
12     </footer>
13</body>

Step 2: Isolate the Core Content with <article>

The <main> element tells us where the primary content is, but we can be even more specific. The <article> tag is used to enclose a self-contained piece of content that could, in theory, be distributed and reused independently (e.g., syndicated as an RSS feed).

  • Examples include a blog post, a news story, a forum post, or a product description.
  • Typically, the page's primary <h1> heading is placed inside the <article>.
1<main>
2     <article>
3          <h1>The Main Topic of the Page</h1>
4          <!-- The core text, images, and videos that make up the article -->
5     </article>
6     <!-- Other content within main might exist here -->
7</main>

Step 3: Separate Supplemental Content with <aside>

Now that you've ring-fenced your core content with <article>, what do you do with everything else? Things like related post links, author bios, advertisements, or pull quotes.

This is the job of the <aside> tag. It defines content that is tangentially related to the main content around it. It's for supplemental information that isn't part of the primary narrative.

1<main>
2     <article>
3          <h1>Page Title</h1>
4          <!-- Core content -->
5     </article>
6
7     <aside>
8          <!-- Supplemental content like related articles, ads, author bio -->
9     </aside>
10</main>

By using <aside>, you're explicitly telling search engines, "This content is related but secondary. Don't weigh it as heavily when determining the main topic of this page." This prevents the topics of your related articles or ads from diluting the focus of your main content.

Using the Tags: A Practical Example

Let's apply this to a blog post reviewing the "BMW X5":

1<main>
2     <article>
3          <h1>BMW X5 In-Depth Review: Performance and Features</h1>
4          <!-- The full review of the BMW X5, with text, images, etc. -->
5     </article>
6
7     <aside>
8          <h2>Related Articles</h2>
9          <ul>
10               <li><a href="/mercedes-gle-review">Mercedes GLE Review</a></li>
11               <li><a href="/audi-q7-review">Audi Q7 Review</a></li>
12          </ul>
13          <!-- An advertisement could also go here -->
14     </aside>
15</main>

This structure makes it perfectly clear to a search engine:

  1. The main subject of this page is the BMW X5 review.
  2. The links to the Mercedes and Audi reviews are supplemental and should not be used to define the primary topic.

How and When to Use the <section> Tag

The <section> tag is perhaps the most commonly misunderstood semantic element.

A <section> is a thematic grouping of content, typically with a heading. The key is that it groups related content into a distinct section within a larger document.

Common Mistakes:

  • Using it as a generic <div> for styling. This is incorrect. <section> is for semantic structure, not layout.
  • Wrapping everything in <section> tags. If the content inside isn't a distinct, related block, a <div> is often more appropriate.

The Best Use for <section>: The most common and correct use of <section> is inside an <article> to break a long piece of content into logical parts.

Let's refine our car review example:

1<article>
2      <h1>BMW X5 In-Depth Review: Performance and Features</h1>
3      <p>Introduction to the review...</p>
4
5      <section>
6           <h2>Exterior Design and Styling</h2>
7           <p>Detailed thoughts on the car's exterior...</p>
8      </section>
9
10      <section>
11           <h2>Engine Performance and Handling</h2>
12           <p>Detailed thoughts on how the car drives...</p>
13     </section>
14
15     <section>
16            <h2>Interior Tech and Comfort</h2>
17           <p>Detailed thoughts on the inside of the car...</p>
18     </section>
19</article>

Here, each <section> has a clear theme (Exterior, Performance, Interior) and a corresponding <h2> heading. This creates a clean document outline that helps both assistive technologies and search engines understand the flow and structure of your content.

Key Takeaways for Better SEO

  1. Structure is King: Use <header>, <main>, and <footer> for high-level page regions. Use <article> to define your core, self-contained content, and <aside> to separate it from supplemental "noise."
  2. Focus the Engine: A clear semantic structure prevents the topics of secondary content (like ads or related posts) from diluting the topical authority of your main content.
  3. Separate Structure from Style: Never use semantic tags for styling. Let HTML handle the structure and CSS handle the presentation.
  4. Use <section> Wisely: Use it primarily to break up a long <article> into logical, thematic parts, each with its own heading.

Taking the time to implement a proper semantic HTML structure is a foundational SEO practice that can pay significant dividends. Run a SeoSpeedup Site Audit today to see how your site's structure stacks up and identify opportunities for improvement.