This article was updated on April 26, 2017, and originally published on April 6, 2017.

A look at a list of the world's largest social networks unsurprisingly pegs Facebook (NASDAQ:FB) at the top. But what may be surprising to some is the degree to which Facebook dominates the top social networks with other Facebook-owned platforms beyond the company's core Facebook app. Facebook currently owns four of seven of the world's largest social networks when measured by monthly active users.

Among Facebook's social networks, its 2014-acquired messaging app WhatsApp is one of the company's most impressive. As the world's second-largest social network (tied with Facebook Messenger and behind the core Facebook app), WhatsApp is quickly growing into a force to be reckoned with.

WhatsApp logo

Image source: WhatsApp

So, how many monthly active users does WhatsApp have today? As of Facebook's last update on the messaging app, 1.2 billion.

Here's a close look at some key facts about WhatsApp and its users.

What is WhatsApp?

Acquired in in 2014 in a pricey deal valued at about $19 billion, WhatsApp was Facebook's first major bet on messaging. At the time, the app primarily served as an alternative to SMS messaging, enabling text and photos while avoiding carrier fees for texting. But the internet-messaging app has expanded to include audio and video calling and the ability to send documents, location, and more.

In short, WhatsApp is a version of Messenger, though primarily based on phone numbers rather than internet-based usernames.

A close look at WhatsApp's user growth

WhatsApp's growth has been astounding. When Facebook acquired the service in 2014, WhatsApp had 450 million monthly active users. And it acquired all these users in a very short time; WhatsApp was founded in 2009. With 1.2 billion monthly active users today, WhatsApp's monthly active users have increased about 167% since Facebook acquired the app.

A woman using a smartphone.

Image source: Getty Images

Adding further context to WhatsApp's recent growth, consider that it only took a year for WhatsApp to add 200 million monthly active users. The service's monthly active users increased from 1 billion to 1.2 billion between February 2016 and February 2017.

Today, WhatsApp is used in over 180 countries, and users send more than 50 million messages on the app every day. 

Monetizing WhatsApp

With such a significant and fast-growing user base, Facebook is exploring ways to meaningfully monetize the service. To do this, Facebook CEO Mark Zuckerberg said in the company's most recent earnings call that he wants to focus on opportunities in communication between users and businesses.

Zuckerberg explained, "[G]iving businesses the opportunity to connect in WhatsApp and reach the people that they want and eventually have increasingly -- hopefully transactional interactions -- I think will be a really useful thing on that platform as well."

Going forward, while it's not clear exactly how fast WhatsApp will continue to grow, especially considering its overlap with Facebook Messenger, one thing is clear: WhatsApp has grown into a significant asset for Facebook, and the company will undoubtedly look for more ways to monetize it as engagement on the platform increases. 

Daniel Sparks owns shares of Facebook. The Motley Fool owns shares of and recommends Facebook. The Motley Fool has a disclosure policy.