Okay, we have rough world map and we got all those pesky technical stuff like average temperature of desert of death right.
That would make interesting map for exploration and whatnot, but it is somewhat empty … there are no people.
Here comes second step: Again, we will play games (weeee!). We want to simulate “History” of world now, so there is no better choice that game from civilization series or its free clone.
How it is played is obvious: Load up map editor and replicate map you got from sim earth, place resources and starter cities. You want to watch so put playable faction on some far away island (possibly surrounded by impenetrable mountains) and cheat to get techs that will allow you to watch everything (i.e Satellites), take notes :).
You will eventually end up with more than enough background lore for your world.
Inspiration here is obvious: Generate world and get it right. Imagine MMO where each server would be unique and would have rich, detailed history. Imagine one-man show MMO where hours of new, unique, content consisting of new continent filled with towns, kingdoms, npcs and quests, unique items, maybe even skills and monsters. All added “simply” by clicking button.