[Jack_Trowell]

From what I understand, it sets the map global style : in the empire society for exemple, you should get many towns and cities, and have fewer mystical creature roaming the land and more humans.

In the society of the fallen empire, battlefields should be more numerous, as well as undeads or other dark creatures released/created during the fall of the empire, and the Empire capital can be found occupied by powerful undeads or other creepy creatures (in a AAR, the capital was occupied by creatures from the void)

In the agriculture society, you're supposed to get many famrs and small village, but few forts or cities.

And so on ...