Like a headline on a newspaper or magazine, header tags are used to format the headlines for your website content. They should provide a user with an idea of what your content focuses on at a quick glance. For this reason, search engine spiders also focus on this content as they crawl your site. They will place emphasis on the words in your header tags in determining what your content is about and whether it is relevant to user searches or not. Therefore, including the keyphrases you are targeting for SEO in your header tags is essential. When doing do, make sure that you are not repeating the same headers on more than one page, as duplicate content is eliminated by the search engines and will not help you improve your results. Look for ways to cleanly incorporate the words in different ways, only where they make sense, so that you can enhance the experience for your users as well as get noticed by the search engines.