As far as I'm concerned there needs to be a healthy mix of both IC and OOC chatter to ensure the long prosperity of pretty much any group of role-players. I find myself getting terribly bored by people who go on and on and on about what they had to eat for lunch during what is meant to be a dramatic bit of role-play. On the other hand, I find myself equally bored by role-players who try and take anything and everything that comes their way as potentially IC even when it directly contradicts the situation at hand or the game's lore.
