It's common to use "funny characters" (i.e., non-alphabetic symbols) in Outlook folder names, so that the folders sort in a specific order:

!!Super Important
!Important
All A's
Basically B's
...

Of course, the same principle can be applied to category names:

!Important
@Home
@Work
Project A
Project B
...

But how can you be sure that "!Important" will come before "@Home"? In other words, what's the sort order? This bugged me enough to sit down and work it out. So here's the sort order in Outlook 2007 (American English) for the symbols from an American standard keyboard layout:

  ! " # $ % & ( * , . / : ; @ [ ] ^ _ { | } ~ + < = >
then all the numbers
then all the letters

The hyphen and single quote are (almost) ignored, in that -A sorts after A but before B, and 'B sorts after B but before C. And yes, that's a space character before the ! character, so putting a space at the front of a folder name will make it sort to the very top. Sadly, there seems to be no special character that forces a folder to sort to the bottom of the list.

I'm sure there is an official name and explanation for this sort order, but my search engine fu has failed me. Help me, oh lazyweb!