<h1> is the HTML element for the first-level heading of a document:

• If the document is basically stand-alone, for example Things to See and Do in Geneva, the top-level heading is probably the same as the title.
• If it is part of a collection, for example a section on Dogs in a collection of pages about pets, then the top level heading should assume a certain amount of context; just write <h1>Dogs</h1> while the title should work in any context: Dogs - Your Guide to Pets.

Unlike the title, this element can include links, emphasis and other HTML phrase elements.

The default font size for <h1> in some browsers have, unfortunately, motivated many writers and tools to use an <h2> element in stead. This is misleading to tools that take advantage of heading structure of pages, such as Amaya's table of contents view. Consider using Cascading Style Sheets, which are designed to express the author's preferred font sizes corresponding to elements such as <h1> and <h2>

Vía: www.w3.org/QA/Tips/Use_h1_for_Title »