One of the new tags in HTML5 is the hgroup tag which is used to group a set of headings into a collection. An example usage of the hgroup tag follows.
<hgroup> <h1>Title</h1> <h2>Subtitle</h2> </hgroup>
The hgroup element must only contain h1-h6 tags. Contextually, the new hgroup tag provides new semantic meaning to pages that otherwise did not exist. In the past, header tags have been used carelessly with the exception of the h1 tag for search engine optimization purposes. I can foresee the hgroup tag becoming an important SEO strategy once the support for HTML5 has been settled.