Well, at least there's interest.
Alright, so here's what I'm thinking about a setting: A large continent with a handful of kingdoms/republics/city states(there's always a couple that "were always there" if they were ignored and forgotten before they became relevant). The technology level will vary depending on region, as well as the magic level. I'd likely say that areas with weaker technology have developed stronger magic and vice versa in order to become prosperous.
Also, I'll establish the canon of "named characters". If a character has a name, they're important. Most of these don't die in one hit, and when any of them is dealt a mortal injury, there will always be a chance they can be saved from death provided there is an ally present at the time they receive the injury.
The first two rules of any Free-form RP:
1. No "Autoing": You control your own character and in some cases your own NPCs. While you can cut through hordes of unnamed characters "mooks" with little risk of injury, declaring the success of an attack or magic attack against a named character is against the rules: you may describe the action, but the effectiveness is determined by the other player.
2. No "God Moding": The other guy did something very cool, he described it well, and not only is it his specialty but your own character has no specific resistance or immunity to it. It should probably affect your character in some way or another. When something happens, react appropriately, even if reacting appropriately puts your character into a tight spot.