To an untrained observer, a heading is nothing more than big, bold text. In reality, Web pages can use six different official heading tags, and each one has meaning. Sure, you could make your text larger or bolder using lots of other codes, but unlike bold or italic, putting a real heading tag on a headline does much more than emphasize the line of text. It tells search engines that the text is important, and the numerical code tells them how important it is.
For example, a <h1> tag, the most important one, is used for the main page heading. The text within an h1 tag is supposed to describe the entire page. An <h2> tag is used for the primary subheadings that begin each main section of the page. The <h3> tag would be used for secondary subheadings within the main sections. And so on – <h5> and <h6> text is usually pretty small!
Headings should serve as an outline of your page.
A good search engine should look at the h1 heading and consider it the most important, most descriptive text on the page. The h2 headings should be considered second in importance. But search engines can’t assume that Web page headings provide a sensible outline of the page, because webmasters usually use heading tags to control the size of the text.
The best way to use heading tags
The best way to use heading tags, however, is the way you learned to do outlines in school. Start with h1, then h2, then h3, as far down as you need to go. Don’t skip any levels. Maybe you don’t like the way that affects your design. Maybe your h1 headings or your h2 headings end up too large or small. That’s understandable. Fortunately, you can use cascading stylesheets (CSS) to change the size or other characteristics of each type of heading. Your page can be attractive as well as meaningful.
Make every heading meaningful
Because screen readers, as well as search engine spiders, use headings to interpret a Web page, don’t add any heading tags that don’t add meaning, that don’t fit in the outline. If all you want to do is to emphasize some text, you can use <em> or <strong> tags, or add some CSS that makes the text look just the way you want.
Headings add beauty
Headings do have a graphic purpose, of course, and not just a semantic (meaningful) purpose. A page that’s broken up with headings is easier to read – it isn’t a mass of gray. If a page is nothing but heading, it becomes a mass of black, like a 19th century newspaper advertisement. Headings should draw your visitor’s eyes to your most important points. If you use the right (official) heading tags that search engines understand, they will also draw search engines to your most important points. Which is what you want.