One Billion People Log In to Facebook for First Time - The New York Times

Mark Zuckerberg noted "it's just the beginning of connecting the whole world"

"For the first time, a billion people used Facebook in a single day on Monday. Facebook’s chief, Mark Zuckerberg, observed the occasion with a post on his Facebook page, saying that one out of seven people on Earth logged in to the social network to connect with their friends and family."

One Billion People Log In to Facebook for First Time - The New York Times