The Drupal taxonomy module permits the creation of a heirarchy of categories. There can be a number of these collections of categories which are each called a vocabulary.
Subversionary has two vocabularies: Blog and Subversionary. Each page of the site is put in a number of Subversionary categories and these are used to index the site.
To get the best out of this site look for the navigation block in the right-hand column (if you are logged in it's title will be your user name). Links with an arrow to the left open the navigation when clicked. E.g., if you click on Projects a list of all projects will show as the page content and the menu will open up to show all the available sub-categories. I am interested in finding a client so I click on Client and get a list of Subversion client pages.
At any point you can click on the page title (e.g., TortoiseSVN) and the full page will be shown.
This site uses modern web standards so any recent browser will display these pages properly. Older browsers may not lay the pages out correctly but the content should be accessible.