Worldbuilding can be a pretty big task, especially when the world we're creating needs to be accessible to everyone joining it. That being said, it can also be easily broken down into a few basic categories, and different users can be assigned to different areas based on their interest. A few things to keep in mind:
Areas of InterestEdit
While it would be possible for me to sit here and create a nation RPing world on my own, I don't really have time to do so. On top of that, the world would likely seem more like my own private creation, than something we can all work within togeher. Thus, I think it's best that we split the work amongst ourselves, and each introduce our own specialties and experience to this world. We can divide our work in a few seperate ways:
One option is to literally carve the world up into areas of interest, and thus handle our own specific areas as we want to. This could be very straightforward, but might result in these areas being somewhat insular.
A second option would be for us to each handle different cultures, and thus filling in particular cultures in particular areas. Thus I might handle everything related to humans, or just related to a particular human culture, and someone else might handle everything related to Elves, and so on. This would likely be less insular than the first option, but deciding where these cultures go might be difficult.
Another option would be special interests, where we each handle a particular aspect of the world. Thus I might handle the world's history, while someone else might handle current affairs, while another person might set out to describe the world's cultures in detail. This could work, but might be awkward and difficult to handle, while also being a lot to handle across a wide area; especially when it comes to intersecting work.
A Big MixEdit
The finaly option would simply be to let people randomly decide what they want to do out of any of these divisions. It'd be messy and could result in conflict, but it'd certainly be... natural.
We also need to establish some common knowledge facts about the world, like levels of magic and the way it works, and so on. These are all constants throughout the world, and will need to factor into our world building. This is probably best discussed together in chat, so just keep it in mind until we do.
I'm calling this section flow, since I can't think of a better word for the moment. What I mean by it is, although we're all creating seperate areas of this world, they need to intersect almost seamlessly. Simply because one area of the real world barely interacted with another, this doesn't mean that one never affected the other. Look at the Roman Empire and the Han Empire, although the two never even established diplomatic relations, the relative excess and demmand for certain resources like Silver and Silk, drove the early silk road and drastically changed the economic situations in both empires. Thus, we want to make sure that physical, political, and cultural boundaries are permeable. This will require keeping an eye on one anothers' work, and collaborating where possible. This will also be something to consider for regular users when creating their own nations.
I hate to come in here and start talking the way I specifically want things to be, especially when this is a collaborative project, but I would generally prefer that we keep things fairly realistic here. By this I don't mean that we need to only have Humans, and that dragons should never appear. Rather I mean that we shouldn't create a world full of magical fairies and princesses. This is mainly to try and keep people serious about this idea, which is important when all of our actions have consequences. Obviously this isn't some draconian order, but it is something to keep in mind.
We've got a pretty sweet map, which I'll insert below, thanks to the generosity of one Deviantart stock provider. Of course, this map is entirely blank, so it's going to need some lines and stuff drawn on it. I can do this, but I'm no artist, and if someone's willing to volunteer to make this map both pretty and functional, please let everyone know. Your skills would be greatly appreciated!
Apparently the map is too bloody big for Wikia to deal with, so I'll just stick a dropbox link below.