Rule 9: Avoid HTML Tags (Optional)
Because you can name tags anything you want, you could use tags reserved for HTML markup, such as <h1>, <p>, <li>, and so on. Although permissible in XML, avoid using such tag names unless you want the data to be formatted that way when it’s viewed in a browser window.
Editor's Note: For more great books on using InDesign CS3, check out the following titles:
Instant InDesign: Designing Templates for Fast and Efficient Page Layout
InDesign CS3 for Macintosh and Windows: Visual QuickStart Guide