We have just published our DITAinformationcenter on a Drupal 7 web site. It contains information about DITA and the DITA Open Toolkit at the 1.2 standard level. Now that we have published it on Drupal, you can search the topics by metadata tags or text and you can also see how to combine formal structured documentation with informal blog posts on a single site and at a reasonable cost.
Dick and Anna