Since everyone is too busy arguing in the chatterbox, I'll "answer". (:

Last time I checked, the HTML Other Users Nodelet sort users first by XP (not number of write-ups) and second by "age" (whether that is determined by "user creation time" or by "user homenode ID number" is unclear from outside).

The Tk Chatterbox Client sorts users alphabetically (except for my chatterbox that I patched specifically to avoid this).

The new HTML Chatterbox Frameset sorts users by "age" (see above).

        - tye (but my enemies fear my reverse engineering skills)