Header elements can be used to keep a, logo, search form, and a contents list linking to subsections on a page. But thats not all, read more about headers in the reference.

Example of nav, article, section, header, and footer.

This is the first section in the page, which is started by the Article element. Any subsections should be marked up using the section.

Using the section element

This is a subsection which is marked up using the section element, it indicates that this is a subsection of the main article. Individual blog comments or forum replies, should be marked up with nested article elements.

Nested article elements

This is an article, nested inside the main article. When doing this, remember that this should mainly be done for blog comments, forum replies, or guestbook posts, etc.

Nested articles, will most likely be rendered with a left padding. Its therefor a good idea to reset the default browser style.