Facebook Messenger is an instant messaging application, much like Facebook's online chat. Yesterday, Facebook updated Messenger for iOS and Android with a new feature: voice messaging. Although that's not a unique feature, it seems that Facebook is paving the road to something bigger: voice calling. Currently only Canadian users can test the new VoIP feature, which will be rolled out to everyone "over the next few weeks," according to the changelog on Apple's App Store. Voice messaging is already available to everyone.
You can send a voice chat by tapping the '+' icon to the left of the input field. After you tap 'Record Voice', you have to hold the red record button while you're speaking. Releasing your finger will send the voice chat, sliding off will cancel it. If you're a Canadian iOS user, you can try out voice calling by simply tapping the 'i' button in the top right corner and choose 'Free Call'.
When you take Facebook's user base into account, this could mean serious competition for more established VoIP providers like Skype. Last month, Facebook dropped the requirement of having a Facebook account for its messaging app, possibly as an attempt to lure WhatsApp users to Facebook.