Dwarf Fortress Online...
Here's an idea:
When you create a character, you start as an adventurer. You can start in the wild or in a town of your choice.
As an adventurer you can go from town to town and visit dungeons. It is also possible to switch to "Paysant mode" if you are in a town. If not, you can create your own if you have at least 6 other players with you.
As a paysant, you are confined to your town's area, but now have the possibility to build and become someone important (manager, book keeper, sheriff, etc). To this you can add an Eve Online like system in wish you assign your character to a specific task (building, crafting, fishing, etc) while you are not playing. Towns can have certain rules enforced by players (like RP, working, not consumming to much resources, etc).
The competition between adventurers would be about having the best equipment, collecting the largest number of postcards, killing reknown monsters. Between the paysants, it would be about having a job and being respected amongst their community. The way jobs are acquired is something else to think about (could be elections).