Using drupal's taxonomy for navigation
lists only nodes tagged with tid
lists nodes tagged with tid or any child y levels deep.
lists nodes tagged with tid and all its children.
lists nodes tagged with tid1 OR tid2
lists nodes tagged with tid3 AND tid2
Any number in the square brackets are the description for a number and the brackets shouldn't be entered. If you want to see nodes tagged with the id number 12 you would enter "taxonomy/term/12". [tid], [tid1], [tid2] is the "term id" and [deep] is how far down in a hierarchical list to go.
To learn what the id is for a specific term is you look at the URLs of the different items listed in the taxonomy section (in Drupal site administration). Place the cursor over any edit term and look to the status bar at the bottom of the browser.