The history and the impact of the scoop that earned the Pulitzer Prize for The Guardian and The Washington Post for "public service" rendered to the world. What in Italy is known as Datagate is not merely a diplomatic/technological affair that involves distant countries, but a great example of how journalism can contribute to a more informed - and hence freer – society.
For background reading, see February 2014 interview of Annie Machon by Carola Frediani entitled Snowden and the war on whistleblowers