Like other religious institutions, but hecka bigger, the Vatican struggles with figuring out how to control its message in the Twitter ecology. The challenge top-down religious institutions face (like the one I belong to, for example) while trying to communicate online with people in and out of the faith could be called the "rhetoric of cool" problem, to nod to Jeff Rice's book. New new media has made it uncool for institutions to have a web presence devoid of user-generated interfaces or content. If you can't comment on something, the conversation is over.
Official digital monologuing is uncool. Then again, the Word has always been--as the hardcore band Minor Threat used to sing/scream--out of step with the world. Revealed religion, you could say, can be a conversation-stopper, as Richard Rorty said it was, because as speech act it purports to lay down divine standards for belonging, believing, and behaving. (I take the three B's from Putnam and Campbell's incredible new book, American Grace.) However prophetic the pronouncement, the message still needs to connect with the audience--the Iron Law of rhetoric?--and digital literacy transforms our expectations of how information flows and collective ethos is constituted. It will be fascinating to watch/analyze how or whether the Vatican listens to its more progressive officials and leans cool.