Last March, Facebook acquired group messaging app Beluga for an undisclosed amount.  No news surfaced as to what Facebook’s plan was for the group messaging app until Tuesday afternoon when they launched the Facebook Messenger app, available both on iOS and Android devices.  And just a day after launch, Facebook Messenger is already the top free app in the Apple App Store.

The launch is to be a take on RIM’s BBM and Google+’s messaging feature for Android users.  BBM only allows free messaging between BlackBerry users while the Facebook Messenger features the usual messaging and chat functions of the Facebook app but it’s much faster, and it also allows users to send SMS.

Though many apps and social networks have already incorporated instant messaging and text messaging, what sets Facebook Messenger apart is that you can actually send a text message directly on your friend’s phone if their number is listed in their Facebook page.  But this can only be done with user permission, so as not to raise any more privacy concerns.

The push notification option has also been modified in that allows real-time notifications. The notifications can also be altered to your preference as which notifications to silence, set the time for silencing notifications from groups or in a certain period of time.

Aside from this, Facebook Messenger will soon feature a video chat mobile option.  Hackers have already found trace evidence of its existence.  Though the feature is not yet release, people are already looking forward to it as Facebook might also launch a group video chat feature.

This is a great app as it allows real-time communication within Facebook at a private level, and extending beyond the app itself.  Facebook’s ramping up its mobile efforts as mobile devices allow for more personalized correspondence and actions around our relationships (contact book), even as competition is on the rise.