Some verbal/written exchanges convey almost no meaning but are part of the protocol of conversation. For example, somebody greets you with "How are you?" and they're not usually not listening for actual information, just for you to say, "Fine," or similar. Or when you go through any sort of service transaction, it seems like half a dozen "thank yous" are exchanged between both parties.
Is there a term or phrase describing the phrases we use for maintaining the facade of politeness?