The actual idea I'm going to talk about came up on IRC when discussing some ideas about how a quest system should work. One side was saying that history and such should be intertwined into the quests, an important part of them. The other side was saying that some people don't care about settings info and history and we shouldn't make them sit and learn about something they don't want to know about every quest they do.
After thinking about it I came up with an idea that I'd like to see in planeshift oneday, something that would apply to quests, leveling, and roleplay and would help them seem less like 3 seperate things.
When it comes to leveling I think that knowing the settings and things like that should help you level, possibly help you even level faster than not knowing it. For example, if there was some research that you could find in the DR libarary about the carkrass written by Londris. This research would tell anyone hunting it everything from how powrful and fast to any weaknesses it has. Londris mentions a weakness against crystal way spells. A player who happens to be hunting carkrass would know to use crystal way.
Notice I say player. It doesn't matter if you think of yourself as a roleplayer or you prefer leveling. The information is there to anyone who wants to seek it. It doesn't force a 'roleplayers' to level or 'levelers' to roleplay. It simply helps players, no matter who they are. You could do the same kinds of things with all kinds of the monsters, maybe not all of them but a good amount.
You don't have to make the info open either, maybe hidden/secret depending on the monster. Maybe tefusangs have some kind of weakness to bludgeoning weapons like hammers so anyone who uses a hammer will have an advantage but other weapons do little. It makes leveling a bit more challenging (and interesting in my opinion) and makes information something more sought after. It doesn't make it immpossible to level without knowing the info nor immpossible to roleplay without leveling.
As for questing its more or less the same only with an option. Lets say Leverus asks you to go and collect rat eyes for him. Before you go he'd ask something like 'would you like to know more about rats'. Say no and you go off on your way and fight the rats. Say yes and he tells you a bit about them, possibly whether all their parts are useless, maybe ones that are useful, weaknesses they have, etc. If you say no killing rats could be difficult, if you say yes it may give you some edge. Yes or no, you now know Leverus knows about rats. Maybe later Sharven needs you to make a special potion but doesn't know what part of the rat is needed. Leverus knows all about rats as you well know and can tell you what parts are helpful and what aren't.
Maybe someone wants a tefusang skin. You try and kill one but you fail. Then you ask around and a player tells you the tefs weakness is hammers. Maybe another NPC who you find out knows about tefs tell you. I'll admit, I've no idea how these things would be implemented, all the hard complications about it etc
Either way I think its a good idea and at least something to keep in mind. To me it makes the 3 things in the topic seem more like one thing than three.