A message board isn't meant for chatting. It's meant for messages to be posted which people respond to. It can take too long for responses. A chat, on the other hand, allows for instant responses, very fun discussion, and much more which you just cannot get from a message board.
I can tell you that a few very nice effects (no, not some little stuff thought up in a few seconds) have spawned from the IRC chats. It's a nice way to get instant answers, discuss thoughts with others, and just chat in general.