When Facebook acquired WhatsApp four years ago, the number of messages being sent via the messaging platform was about a third of what it is today.
Judging by this $4, it isn't slowing down. As of May 2018, about 1.5 billion users are sending 65 billion messages via the WhatsApp mobile app and web client per day, up from one billion a couple of years after the company launched in 2009.
That's tremendous growth for WhatsApp, and it makes Facebook look very smart for having spent $19 billion on it in 2014. Given Facebook's massive social network - more than double WhatsApp's 465 million monthly active users at the time, and a messaging app of its own - people weren't sure what an app like WhatsApp could bring to the table.
WhatsApp still doesn't bring in ad dollars, but the acquisition did give Facebook $4 in the world, meaning users are leaving one-product competitors like Snap and Skype and instead choosing one of the many services operated by Facebook.
![Chart of the day](https://static-ssl.businessinsider.com/image/5af200632c43091d008b4626-1334/chartofday5818.png)
Shayanne Gal/Business Insider