Of course, the AI of Boundless did not just make this announcement and leave players hanging. It came with subsequent screens that dutifully informed players what these three things were, how they functioned, and how to utilize/join them.
The Area Rankings displayed the top 10 of various different categories. For example, top 10 kingdoms in an Area Zone, top 10 dungeons, top 10 blacksmith NPCs, top 10 blacksmith players.
Just, any category at all, no matter how small, was included and calculated. There were even Class Rankings, as in the best within a single class like an assassin, swordsman, spellblade, etc.
It was a comprehensive way to distinguish the best in various areas worldwide. The Continental and World Rankings were just bigger versions of this concerning larger pools of choices.