Facebook number of active users has reached to 2 Billion in this year. Facebook had its 1 Million active users 5 Years ago. And if Facebook was a country then , Facebook would be the county with Maximum population. Even the current country with maximum population , China has only 1.34 Billion people. And YouTube is ranking the second position with 1.5 Billion. And WhatsApp and Messenger ( Both belong to Mark Zuckerberg ) has a monthly user base of 1.2 Billion.