@ Distro: Okay, I can accept that as a valid reason. I still don't think I'd glom onto the world-building thing, even if I had a whole group of pals doing the same around me, but if you're the sort who is naturally inclined to this kind of gameplay, I can definitely see the fun factor being magnified in multiplayer.
My last server had children as young as 9 and adults as old as 60 or so.
Doubly so if you're sauced like Todd.