Facebook Messenger App transmits calls using your phone's
broadband connection (3G, 4G or Wi-Fi)and it takes megabytes from your data
plan instead of your monthly allotted voice minutes from your cellular carrier.
It won't be the way of normal call, but show up as a push
notification and you can only connect with a conversation partner who also has
Messenger installed on their iPhone.
The VoIP features in the Web version of Facebook were built
using Skype's technologies, while the calling technology in Messenger is all
Facebook.
There's no way to ring up a Facebook friend who is logged in
through the website, and there isn't any way to place a call to a ten-digit
phone number. Calling is still absent from the Android and BlackBerry versions
of the Messenger app.
Unlike Google Voice and Skype, Facebook is 100% platform
neutral. Facebook doesn't care if you use its app on an iPhone, Android,
Windows Phone, BlackBerry or Ubuntu.
