On Sept. 14, at 12:45 p.m. PDT, Facebook reached the mark of 1 billion monthly active users. “Helping a billion people connect is amazing, humbling and by far the thing I am most proud of in my life,” wrote founder and CEO Mark Zuckerberg in a brief announcement post. “I am committed to working every day to make Facebook better for you, and hopefully together one day we will be able to connect the rest of the world too.” The company shared some facts to go along with the announcement, including that the median age of a Facebook user is 22 and that the social network boasts 600 million mobile users. In an interview, Zuckerberg emphasized the company’s focus on mobile, saying that he expects more money to be made per amount of time that people are spending on mobile. (Facebook Newsroom, Businessweek)