These marks can be found all across Vana'diel in varying locations. They don't share any common purpose - they're just special "hidden" spots that are used for different quests, missions, spawn points, etc. Sometimes you'll need to trade an item to one of these ??? and other times you can just click on it.
It may not be wise to randomly click on any ??? that you find, either. Some will spawn very hard monsters that you may not be ready to take on! But of course...if there's a button, there aren't many who can resist testing it...
Click on the position to open a map to the area in question. For areas with multiple maps, it goes directly to the area containing the ???.
|La Theine Plateau||(G-6)||Used in Quest: I Can Hear a Rainbow|
|Temple of Uggalepih||(F-10)||Used to Spawn: Death from Above|
|Valkurm Dunes||(H-9)||Appears only during dust storms/sand storms|
Obtain item: Sunsand
|Valkurm Dunes||(B-7)||Used in Quest: Messenger From Beyond (WHM AF1)|
|[[<zone name>]]||(?-?)||<insert quest, NM, or other purpose this ??? serves>|