Two key paragraphs here:
"The Pope's presence on Twitter is a concrete expression of his conviction that the Church must be present in the digital arena,” the church said in a written statement to reporters. The pope’s account on Twitter, the statement said, “can be seen as the 'tip of the iceberg' that is the Church's presence in the world of new media.”
A Vatican official told CNN the pope will be composing the tweets for the new account himself. For the first tweet from the account, the pope will also press the button to send the tweet himself, but after that others will send the tweets on his behalf.But what effect will this really have on Catholics and Catholicism? The only downside I see from this is the potential for the the Pope to spend time composing tweets that would be better spent doing something else. But I suspect that will not be a problem; tweets are short, and he doesn't need to send them that frequently to keep a presence.
So the real question is: what is the upside? Younger Catholics on Twitter will surely find this a neat thing. It give them an additional and convenient way to feel connected with their Church's leader, which would imply a slight increase in their religious capital. And it also allows the Pope a direct route for reaching out to younger Catholics with brief messages of faith, devotion, and inspiration. This is not likely to generate hordes of converts into Catholicism, but the modest benefits in building ties within the Catholic community seem real.
With almost no downside, and a little upside, it appears like a smart move to me.
UPDATE 13-Dec-2012: GetReligion reviews some of the articles about the Pope's first tweet here.