I have some answers of my own in mind, but I'm betting I haven't thought of everything, and I'm interested to see what people come up with. The creativity and wisdom of a large group could completely blow my assumptions out of the water, in other words :)
It's a bit spoilerish, if you're sensitive to such things. However, it's more about the setting than the story. It would be akin to reading a role playing setting book, and learning the world's quirks, without knowing the dungeon master's adventure plans. (e.g. learning that the Spelljammer universe consists of crystal spheres and phlogiston, but not that the DM plans to bestow a Cloak of the Void to you, or pit you against the leader of the Rock of Bral)
If you'd like to participate, you can find the question here. I'd love to hear what you think!