You start off with letting people DL this easy and helpfull addon named Cartographer
Cartographer | World of Warcraft Addons | World of Warcraft @ Curse.com
Now make a quest ingame, like named
<Insert Riddle Here> Explain :Code:"The Start of the Clue Hunt" <Insert Riddle Here> <Insert Cords Here>
A simple, or hard riddle or question such as "I am a bee, the truesure is in a tree!" wich obviolsy points to darnassus, go to darnassus and open up the map (map UI wil be replaced with the cartographer UI) and find the cords inserted in the quest, there should be an object and it takes you to the next riddle and cords.
<Insert Cords Here> Explain :
Cords, they are included in the Cartographer addon, they are the XX,X XX,X notes, such as what it says on the pic Cursor: 95.6 -2.6
Make a couple of these quests, make them followups and gg people wil be happy with doing them for the next hour or 2