Some great explorer has found a new continent and
players can sail there each boot. The continent
is created on each boot randomly and players can
explore it.
From ?-marked places they can find monsters lairs
(also could be created by some random) or people
who might have some quest that players can do(like
bringin some stuff from some special place, and
they could give general direction where that place
lies.
At some ?-places players could meet band of bandits,
group of minotaurs etc. From some people could find
ore mines or maybe an hidden cache of rare materials
like dragonscale.
Some specialist sailors could be found from there,
maybe as prisoner of some nasty monster. Magical
item which has broke to many pieces sounds nice idea
too.
Theres helluva lot encounters that could be used
there. Though it should be limited how many places
you can enter /10mins or so.