Facebook introduced the standalone app in 2011, but it didn’t take off until 2014, when Facebook removed private messaging from the main Facebook app. Mobile users had to either download the Messenger app or use Facebook’s mobile site for messaging. (Desktop users can still send and receive messages from the Facebook website.) The move to split off messaging caused confusion and a fair amount of user outrage, but many ended up downloading the app. The number of people using the Messenger app grew from 500 million per month in November 2014 to 900 million per month in April 2016. In June 2016, Facebook began informing users it would soon strip messaging out of its mobile site. That will make the app the only way to send mobile messages on Facebook. “Right now, we have two of the top messaging apps in the world; 900 million people use Messenger every month, and 1 billion people use WhatsApp every month,” Facebook CEO Mark Zuckerberg said during the company’s Q1 2016 earnings conference call. Get the full story at eMarketer