The just released "voice message" feature for Facebook's Messenger app lets you add audio to your text-based conversations — but if an additional testing phase of the app goes worldwide, it could let everyone replace their phone bills with Facebook calls over the Internet, for free... and forever.

As of launch, these voice messages work more like voicemails mixed with texting — you send them back and forth, rather than as an interrupted conversation. In between text-based conversations, Facebook Messages fans can choose to "record voice," which will lead to the screen pictured at right. Pushing the red button allows for a voice message up to 60 seconds long, which you can then send to a friend. 

That feature alone won't supplant phone calls as you know them. But along with the new text-and-talk capability of its Messenger app, Facebook is also testing VoIP calling, which will allow for a person-to-person connection that could potentially take away from traditional talk time because it works just like a regular phone call — only with data instead of minutes. Facebook is only launching the VoIP (or Voice Over Internet Protocol) aspect of the app in Canada, for now. But if the social network transforms its testing into a worldwide rollout, we could see it catching on as a way to talk on the phone... without having to talk on the phone. Here's how:

More Contacts than Skype  

Lots of other apps have VoIP capability, like Skype, for example. But Facebook has the right people. Your roster on Messenger probably includes a lot of the same names in your phone's address book. And while you probably have more Facebook friends than cellphone contacts — the social network is a less intimate means of communication — you're probably already connected via Messages with all of the people you'd want to call anyway.

More Contacts than Facetime

Apple's Facetime feature doesn't require a third-party connection, as it works right through the iPhone. It also connects you with the "right" people, like Facebook but unlike Skype. But Facetime only works for other people who have iPhones, and Messenger works for everyone with a Facebook account — and that's more than a billion people. Facebook's barrier to entry is beyond low.

Cheaper than Talking

If you're doing VoIP calls over Wi-Fi, the cost of talking is free — something people with terrible phone connections in their homes might consider. For those using the voice-to-voice calling feature over their data plans, however, the price is higher. Skype says each Skype-to-Skype app uses up 3MB for every minute. On AT&T 3GB of data costs $30/month, meaning each minute of VoIP calling ads up to about $0.03 per minute. On the other hand, 450 typical talk minutes cost $40/month on AT&T, meaning one minute costs about $0.09. 

Your typical talking on the phone come with all varieties of carrier deals, of course — free nights and weekends, free calls within carriers, and on an on. Also, as user habits have changed, cellphone companies have started charging a lot less for minutes and more for data. So, under certain circumstances and over time, traditional voice talking might end up cheaper. Overage charges also differ, with AT&T charging $.45/minute and $10 per extra GB. But, at this point, the VoIP talking won't run up a bigger bill. So, why not? Here's hoping the Canadians pass Facebook's test — for the good of the rest of us.