The importance and compared merits of heading tag in website pages and posts has been (and still is) generously commented and there seems to be little argument about it: heading tags are necessary to boost SEO and improve user experience.
Heading is code name for structure
Heading tags (or title tags) are designed to add two elements to content: hierarchy and rhythm, and one major component to search engine parsing: identity.
Imagine a block of text on any topic that would be presented in form of a big clump, possibly with paragraphs, but without visual effects to outline its essence.
The result is a rather uninviting, uninteresting and inefficient post. Very few would be intrigued enough to read it. There is no clear display of what it is all about, the question it raises or the answer it provides.
The purpose of heading tags from a strictly redactional point of view is to be visually enticing and deliver a sort of summary of the content itself. In other words, they constitute the skeleton of web content from the spine (main heading) to limbs (subheadings) to fingers and toes (lower subheadings).
Heading tags respect the chain of command
Typically, the hierarchy in headers is <H1>, <H2>, <H3> with instances of <H4> to <H6>, though those are rarely used in blogging (more commonly found in web page design to create “sections”).
From 1 to 6, the heading tags wouldn’t dream of pretending to be what they are not.
Heading and subheadings are not designed to just format the text. In fact, they are not format elements per se. The font size, color and style are merely set to make them stand out and highlight their respective role. As a good practice, no tagging should be inserted in the body itself.
“Tag, you’re it”: how heading tags impact SEO: <H1> – The main topic. What we will talk about, hence its prominence (that’s a boss).
Heading is code name for structure: <H2>
Subheading that announces we enter into the topic more specifically and develop the characteristics of H1 honcho (Heading Tags) to H2 (structure).
How heading tags impact SEO
The notation <H> title/subtitle </H> acts like an ID tag for search engines when algorithms parse content and eventually decide how to rank the web page. Not that this aspect only decides whether your landing page will do well or not, but the correlation between heading tags and content is unmistakable.
Headers are unlikely to secure you the top position just because you use them. What they say (or don’t say) and how they are used throughout a site has its importance.
The consensus is there should be only one <H1> per page, and that it should mention your focus keyword. In the case of articles, SEO professionals recommend to place that same keyword in at least one <H2> (and of course, it will be dispersed in the text so a “match” will naturally happen between titles and content).
What they don’t recommend, however, is to replicate heading tags in a page or through the site. They should be unique. Nor should you hammer your keywords in the hope you’ll win the race (the opposite is likely to happen). Lastly, unless ranking is not your concern, keep the subject line short (heading tags should never become entire paragraphs), to the point and relevant.
In many instances, site owners have no idea of the importance of heading tags, but chances are their web developer knew a thing or two about it. For others, tools in web creation and blogging allow to select a line and make it a header without knowledge of coding. Even if Google and Yahoo and Bing allege they don’t require heading tags to be able to find your site and display it in results, the digital marketers think and know otherwise. And all SEO concerns aside, we have to admit that structured content looks good and reads better.