Hawk Software

Headings (h1-h6) should be used to begin sections; they should NOT be used for font effects (that is what CSS is for).  Using one h1 tag, and progressive h2-h6 tags not only creates a page structure which is easy to scan and find relevant content for sighted users, but it enhances accessibility for users of screen reader software.

When creating a page, it can help to visualize the headings like this:

<h1> page name
    <h2> major section
        <h3> subsection
        <h3> subsection
    <h2> another section
    <h2> another section
        <h3> subsection
        <h3> subsection

And if that is not enough motivation to properly use headings, it is likely that search engines use headings when calculating page rankings.