Separate to the existing Facebook app, Facebook Messenger enables you to more easily send messages to friends.
Messenger is a separate app, so it only takes one click to get to your messages or send a new one. Messages are delivered through notifications and texts, so your friends are more likely to get them right away.
You can use Messenger to reach all of your friends — whether they’re on Facebook or in your phone contacts. All you have to do is type the person’s name.
A clear challenger to Apple’s upcoming iMessage and the existing BlackBerry Messenger service, Facebook Messenger likewise uses data rather than SMS messages to communicate with contacts.