The professions titles were gained when people had to quest for their professions...
the Powerful - Enchanter
the Sly - Rogue
the Holy - Cleric
the Fierce - Warrior
Before scripting came into play you had to wait for either Cory or Ben to be on-line playing one of the trainers, who would then send you on some quest to retrieve several items - which usually cost you lots of time and money, and the title was a reward for completeing all the quests.
The stature titles are given to those people who promote the game, by encouraging people to at least visit the main page to see what the game is about. Those in places 2 to 10 get the title Lord, and the person who occupies the top spot gets High Lord.
It was only recently the title The Noble was introduced to offer something back to the premium players. As already said, this is to give something a little bit "gucci" to those people who help to pay for the running of the game. It will also identify those people who are premium players to everybody else.
There is one other title that anybody can have... the Marked - but I'm not going to tell you how you can get that, although it is open to anybody - not just premium players