Looks like an early version of the world map. Notice the Undermine (bottom island), the Maelstrom (with Nazjatar nearby)...interesting that it looks like a crack in the world. Since the Old Gods are chained beneath the surface of the world, and the Naga are their minions, it seems likely that we'll get to encounter them at some point, via the Maelstrom.

Also, you can see Kul Tiras, Tol Barad, the Tomb of Sargeras, and some other interesting stuff.