http://bits.blogs.nytimes.com/2012/10/04/facebook-passes-1-billion-active-users/
The New York Times
Facebook Tops 1 Billion Active Users

<p style="margin-left:20px"><a href="https://www.harvardmagazine.com/2011/11/mark-zuckerberg-at-harvard-and-mit " target="_blank"> <img src="https://harvardmagazine.com/sites/default/files/HM_forWebRedesign_final.png" alt="View related Harvard Magazine article" title="View related Harvard Magazine article">Read more on this topic in <span style="font-style:italic; font-weight:600;">Harvard Magazine</span></a></p>

<p style="margin-left:20px"><a href="https://www.harvardmagazine.com/2008/08/intimate-zuckerberg-high-tech " target="_blank"> <img src="https://harvardmagazine.com/sites/default/files/HM_forWebRedesign_final.png" alt="View related Harvard Magazine article" title="View related Harvard Magazine article">Read more on this topic in <span style="font-style:italic; font-weight:600;">Harvard Magazine</span></a></p>