(Osservatore Romano/AP)

By the time Pope Benedict XVI sent his first tweet Wednesday, the 85-year-old leader of the Catholic Church had already acquired more than 600,000 followers. Using the Twitter handle @pontifex, the pope’s first tweet was as cautious as one might expect: “Dear friends, I am pleased to get in touch with you through Twitter. Thank you for your generous response. I bless all of you from my heart.” By day’s end, nearly 42,000 people had retweeted the pontiff’s words, and the pope had answered carefully selected questions on faith in eight languages.