This means that Messenger is the fourth Facebook product to enter the elite "1,000,000 club," including its other chat app, WhatsApp, Groups, and the main social network (which actually gets more than 1 billion users every day).
Over the last several years, Messenger has evolved from a simple chat app to a full-fledged platform that lets people send each other money, make phone calls, call an Uber, or order flowers.
CEO Mark Zuckerberg has said that the business-potential of a product doesn't become "interesting" until it hits that number. Now that Messenger has, we can expect Wall Street to grill execs about it even more than usual when the company has its Q2 earnings call on July 27.
From Facebook's announcement, here are some other stats about Messenger:
