Facebook passed another milestone, reporting Wednesday that its base of monthly active users passed 1.5 billion for the first time.<br />Facebook crossed the 1 billion monthly user mark in September 2012, so it's taken about three years to add the last half billion.<br />It took just over two years to amass the half billion before that.<br />For comparison, Twitter has about 320 million monthly users.<br />The social network announced another milestone in August, when it said the number of people who accessed Facebook in a single day passed 1 billion for the first time.<br />"When we talk about our financials, we use average numbers, but this is different.<br />This was the first time we reached this milestone, and it's just the beginning of connecting the whole world," Zuckerberg said at the time.
