The news was actually broken because one of the agency journalists covering the Vatican beat could speak Latin. Giovanna Chirri , whose tweet broke the story, said she wasn't sure she could believe her ears when she heard Benedict XVI announce the news, coming as it did after three canonizations.
The news, she said, made her cry. The number of Ms Chirri's followers on her Twitter page  have increased nearly fivefold since yesterday.
B16 si e' dimesso. Lascia pontificato dal 28 febbraio— Giovanna Chirri (@GiovannaChirri) February 11, 2013 
Media outlets are already talking about the frontrunners to succeed Benedict XVI, who will be taken to Castel Gandolfo, the papal summer retreat after he resigns, at 8pm on February 28
February 12, 2013 What yesterday seemed shocking is now more of a liberating gesture for the Catholic Church, say some.
The big question on religious commentators minds is this: will the current incumbent of the Papal Throne's decision hold the door open for future Pontiffs to call it a day when they feel they cannot do the job justice any more?
A French cardinal says Pope Benedict's decision to resign is a "liberating act" for future popes. #POPE — Aretha Frison (@ReRe_Red) February 11, 2013 
The Vatican is dismissing the Pope's recent operation to replace the battery in his Pacemaker as the reason for his resignation, but putting it down to general old age.
Pope to resign. Not sure why all the surprise. He is 85 and tired. Maybe he will start a new trend for future popes.edition.cnn.com/2013/02/11/opi… — Rich Marcello (@RichMarcello) February 11, 2013 
February 12, 2013 But Twitter wouldn't be Twitter without the conspiracy theories, and so here's one  for all of us who might be wondering about what the future will bring the Catholic Church.
St Malachy, who died in 1148, is the Pope Prophecizer. After Benedict, his final pope is Peter. Peter Turkson is 4/1 to be the next Pope.— darren rovell (@darrenrovell) February 11, 2013