This is no longer true as of late 2015. The new definition is "We define a monthly active user as a registered Facebook user who logged in and visited Facebook

This is no longer true as of late 2015. The new definition is "We define a monthly active user as a registered Facebook user who logged in and visited Facebook through our website or a mobile device, or used our Messenger app (and is also a registered Facebook user), in the last 30 days as of the date of measurement." So if they don't use Facebook's website or app, or Messenger as a Facebook user, they don't count. http://www.adweek.com/socialtimes/monthly-active-users-definition-revised/629624 http://www.adweek.com/socialtimes/monthly-active-users-defin...