Major approaches to politeness so far analyse it as a strategy to ensure smooth interaction. Politeness is seen as a norm, the expected thing in communication whose occurrence is not noticed most of the time. In my thesis I argue first for a threefold distinction among expected politeness (politic behaviour in Watts's s sense), unexpected politeness and rudeness. Then I examine how participants can exceed the expectations of politeness and in that way use politeness as a means for communicating something more. I maintain that what is then communicated by polite behaviour is an implicature as defined by Grice. In order to be able to include the interactional implicatures that are generated by polite behaviour, the Gricean framework must be expanded by a Maxim of Politeness. I show that politeness is best incorporated into the Cooperative Principle rather than being a reason for failing to observe it, and so manage to acount for the broad spectrum of its different instances and uses: whether it is expected or voluntary, whether it is a strategy or an expression of emotion. Implicatures are then generated either by observance or flouting of the Maxim of Politeness and they can be classified into a) conventional, b) generalized conversational and c) particularized conversational implicatures.