To elaborate, that might be difficult due to the degree of secrecy involved with some characters and factions in the world and the degree to which having the fluid background we have now allows for people to bring in stuff fairly easily most of the time. The more we define things, the less space there is on the whole. Which is not to say it is a bad idea, just to say, it could be difficult to do right and not just end up making more problems in the long run.