Die Funktion custom_url_rewrite_outbound() ermöglicht in Drupal einen redirect zu einer Subdomain.
With Google, Yahoo, and Bing's announcement of schema.org, microdata is quickly gaining ground as a way to create applications that rely on data from many different websites. In this article, learn how to use Drupal to add microdata to your pages. Easily make your content available for use in applications such as Google's Rich Snippets.
ausführliches drupal wiki howto
Displaying hierarchical content is a common request of database-driven web sites. Drupal gives you great flexibility in doing this without writing a single line of code, using a couple of battle-tested modules.
Drupal 6: complex node synchronization with Pubsubhubbub