I've been following the blog of a game designer named Justin Alexander for some time now. The guy has an incredibly keen eye when it comes to thinking about the way in which game mechanics impact the way we play a game. There is a wide spread myth in circulation today that holds that role playing is essentially just a matter of collective story telling, which, though it relies upon certain rules, is largely unaffected by which system of rules is used in conducting this collective story. I think part of the reason this myth is so popular is that allot of us got turned off by the whole Addition Wars of D&D, and figured "hey, we're all engaged in the same kind of activity here, we're just using different rule sets. What's the big deal? A good DM/Player ought to be able to role play well and tell a good story regardless of which set of rules are used." There is certainly some truth in this, but I think that Justin had done a great job over the years of exposing the fallacious assumption that the rules we use are really immaterial to what we are doing when we roll play.
He recently finished a rather helpful series of blogs on the topic of "Game Structures":http://thealexandrian.net/wordpress/15126/roleplaying-games/game-structures that not only shows how the rules we use to structure our game shapes the way we play the game, but also offers invaluable advice to DMs on how to add new game structures to your campaign that will add depth and versatility to your game while at the same time lightening your load as a DM. Just thought I'd share this since I bet others here might find these useful.