With regards to earning Khookies, I'm thinking a simple 1 Khookie per Post system should be fine. If we're talking one-three line posts, that's the only system independent of GM management that I can come up with.
Getting into goal-oriented khookie earning would be tiresome - though perhaps we can have some kind of 'quest' system where, in addition to the 1 Khookie per Post system, completing quests set by a god will also earn one X Khookies