Browsers’ visual display of headings nested inside `` elements makes it look as if they are assigning a logical hierarchy to those headings. However, this is purely visual and is not communicated to assistive technologies. In this article, Bruce Lawson explains what use we have of `` and how authors should mark up headings that are hugely important to AT users.| Smashing Magazine
Headings are the backbone of the content of a page. A visitor should be able to scan or navigate a webpage using headings to get a good impression of its content.| www.a11yproject.com