Too bad the whole thread explaining all this was removed in the great forum purge.
Ah, that's a good remark, we should fix that.
I Had the Same Query Thanks.
For trophies, I can answer you, you can also access the trophy list via the help menu. Here is it:
New titles can be unlocked by unlocking those trophies, and expert people can specify a custom title.
Finally, ranks are obtained through conditions. Active and expert ranks are obtained after having reached a threshold in terms of messages, likes, and your "like per message" ratio should be at least 2 (if I remember well). Most other ranks (like admin, moderator, professor...) can't be obtained under normal conditions, they are reserved to people that have a specific role (like the forum staff, USFS staff and so on...)