Messenger can be used to contact any of your friends, whether they are on Facebook or in your contacts list on your phone (via SMS). To start a conversation with someone, all you have to do is type their name. The app is an extension of Facebook messages, so you will be able to see all of your texts, emails, chats and messages from conversations with your Facebook friends.
One of the key features of the app is group messaging. You can quickly set up a group conversation and message everyone in that group at the same time. You may choose to add your location to the message thread so that everyone can see where you are located and you can also add photos to the conversation.
This is the first official app that Facebook has released outside of its own official Facebook app. However, it may not be the last as details of a dedicated photo-sharing app that Facebook is secretly working on emerged in June.
The app — which is not available at the time of this writing — is being made available on Tuesday. You can find it by searching for “Facebook Messenger” in the App Store or Android Market.