iPhone users in the U.S. and Canada can now use Facebook's Messenger app to place free calls to Facebook friends.
While Facebook doesn't charge you to use the new feature, it does eat up megabytes from your data plan unless you're connected to WiFi. The social network started testing this feature over WiFi and cellular data for Messenger users in Canada earlier this month. It's not currently available for Android or BlackBerry users.
To use the feature, both you and the friend you want to call must have the Facebook Messenger for iPhone app installed.
To place a call, open the Messenger app and search for a friend. Tap the Info button in the top-right of your friend's conversation page to bring up the screen shown at left. If your friend is using the Messenger app, the "Free Call" button will appear in bold; if not, it will be greyed out.
To place a call, simply tap the "Free Call" button. If your friend's phone is locked, he or she will receive a push notification alerting them of your incoming call. Once they unlock their phone, they can tap to answer the call. Your friend's phone will not ring as if it were receiving typical call.
I tested the VoIP calling feature with a friend and it worked surprisingly well. While my phone was connected to Wi-Fi, my friend's was not, and the quality of the call was excellent—even better than normal cellular calls I receive when I'm at home.
Facebook's voice calling feature may not be practical for everyone—I could find only one friend who uses Facebook Messenger with whom I could test the feature, and if you're not expecting a call, it's easy to miss the push notification.
Despite those limitations, Facebook Messenger for iPhone could have some practical applications: You're likely Facebook friends with those you call most often, and if staying within your monthly minutes allotment is difficult, this feature can free some up.
Also, if you don't have a landline at home, Facebook's calling feature could be a good backup. And if, like me, you don't have great mobile service at home, this feature might be a good solution.
Have you used this free calling feature? Let me know in the comment section below.
Kristin Burnham covers consumer technology, social networking, social business and enterprise collaboration for CIO.com. Follow Kristin on Twitter @kmburnham. Follow everything from CIO.com on Twitter @CIOonline and on Facebook. Email Kristin at firstname.lastname@example.org