Found an interesting article about the Pope's Twitter success. Kind of unexpected, but neat. Anyway, it has some good advice on there too, analyzing why his tweets are so successful. Other than because he's Pope... Calling them "divine tweets" was a good touch.
Success? Come on. His tweets are just random pseudo-altruistic nonsense (sometimes biblical characters are mentioned). Of course that he has so many followers just because of his profession. Nobody would want to read that stuff otherwise.