The article tag, which is used to indicate an independent section

Excellent. We have finished handling the main webpage blocks. We can now proceed to the internal page with the blog entry. It consists of the now familiar header, main content and footer.

The header for internal pages will be duplicated: it will contain the navigation block with a link to the main page. The main page contained a single <nav>, and it was included in <main>, but on the internal pages <nav> is repeated. Therefore, we can include it in <header>.

Only a post is contained inside <main> on the internal page, but later it may contain other sections, such as, for example, a tag cloud. Therefore, we need to enclose the post using some set of tags. Perhaps the <section> tag, which we are already familiar with, would do the job? Yes, that tag would work. But is there something else better?

We have in mind the <article> tag that denotes a self-contained and independent piece of information. A blog post is just such an example of this.

The <article> tag, unlike <section>, can be taken from one place and inserted into another (on another page of the website or on another website), and the meaning of the tag’s contents will not be lost. Examples: an article, a blog post, a forum post, and so on.

<article>
  I am a photo on Instagram. I look great anywhere.
</article>