While the move by Facebook to force users to download the Messenger app may not have been a popular one, the app has reached a whopping 500 million active users.

The number of active users using Messenger has more than doubled in the last six months. Facebook cutting off Messenger access in the regular Facebook app also happened in the last six months, largely explaining the spike in users.

"Messaging is an important part of how people stay connected and since Messenger launched in 2011 we've been passionate about giving people a faster and more expressive way to communicate," said Peter Martinazzi, director of product management for Facebook, in a statement. "Today more than 500 million people are using Messenger each month and we're more committed than ever to make it the best possible messaging experience."

Facebook has had an increasing amount of interest in messaging in recent times. Earlier this year, Facebook acquired popular messaging service WhatsApp for a massive $19 billion.

"Messaging is one of the few things people do more than social networking," said Mark Zuckerberg in a recent Q&A. "In some countries 85 percent of people are on Facebook, but 95 percent of people use SMS or messaging. Asking folks to install another app is a short-term painful thing, but if we wanted to focus on serving this [use case] well, we had to build a dedicated and focused experience. We build for the whole community."

Facebook also recently hired PayPal CEO David Marcus to take over Messenger, highlighting the fact Facebook hopes to monetize Messenger. The move to hire Marcus also illustrates that Facebook had no plans to give up on Messenger despite the sum of money that the company dropped on WhatsApp.

Apart from Facebook's hopes to monetize, the future of Messenger is a little unclear. Marcus recently said in an interview that he was exploring ways for users to directly message businesses, but it is not clear how that would look.

While Facebook owns WhatsApp, the competition between the two messaging services is undeniable. In August it was announced that WhatsApp had 600 million active users, putting it only slightly above Facebook Messenger.

"Asking everyone in our community to install a new app is a big ask," continued Zuckerberg. "I appreciate that that was work and required friction. We wanted to do this because we believe that this is a better experience. Messaging is becoming increasingly important. On mobile, each app can only focus on doing one thing well, we think."