I don't know if there's an awesome search function for the forums, so I apologize if this was talked about earlier and I missed it.
I think it would be really neat if each campaign could have an associated wiki-format place for saving information -- campaign notes, character sheets, setting information, etc. It could probably be set up so that information on the wiki is counted against the game creator's storage quota, so that you don't see people storing a ton of information there and bogging down the system.
It could be a feature limited to subscribers at the $5 or $10 tier, maybe, as a useful incentive that isn't prohibitive to do without (ie, there are other free wiki alternatives, but they would not be quite as convenient.)
If I'm late to the party and people already talked about this somewhere, I apologize!