Heading tags are those tags that identify the importance of a piece of content and elevate it above the remaining content. For example, an h1 heading tag is the most important of all heading tags.
When a page uses the h1 tag it announces to the search engines that the enclosed text is of vital importance and it is usually the topic of the page.
For example, a page about Web Design that uses an h1 tag enclosing the words Web Design identifies to the search engine that the main topic of the page is, in fact, Web Design. This can elevate your page above all others that talk about Web Design if they do not utilize the h1 tag.
Over use of the h1 tag on a single page can be considered spam by the SE’s. This can get the page banned and may even get the site banned.
We find it is usually better to use the h1, h2 & h3 tags in a methodical procedure down the page leaving the most important juice line for the h1 tag.