For WhatsApp, the people just keep on coming.
The smartphone messaging app that Facebook bought for $22 billion in 2014 has hit 1 billion monthly users, according to its official blog.
That's more than double the number of people who were using WhatsApp when the Facebook deal was announced about two years ago.
But WhatsApp is still a long way off the metrics of its mother ship. Facebook reached 1 billion users a month back in 2012. Less than six months ago, it hit 1 billion users in a single day.
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The social network has also made its Messenger app, which has more than 800 million monthly users, increasingly similar to WhatsApp.
Facebook is still tinkering with how it gets money out of WhatsApp. It said last month that it would stop charging the annual $1 subscription fee that some users had to pay.
The next step, according to Facebook CEO Mark Zuckerberg, is to try out new ways for WhatsApp users to communicate with businesses and other groups they're interested in -- like Facebook's system of pages for companies and public figures.
Once those efforts reach the right scale, Zuckerberg said last week, the company can "really start dialing up advertising."
