Someone suggested using MySQL tables of type HEAP (I was thinking shared memory), I think this is a GREAT idea for all of the temporary information like user status and time, but the actual game data needs to be able to be stored in a "command stack" array so when the user does (sooner or later) pick it up it, the commands can be executed in the exact order they were received (to properly update the game map, etc). Also, the multi-player game world persists even after the player stops playing. So next session he will need to update his map accordingly (if he was affected while he was offline). But I'm still not clear on how to best accomplish this last part in any other way besides using one flat file (appending commands to the command stack) per user.