Facebook Messenger allows you to use the messaging feature of Facebook without having to launch your browser. The app makes communicating with your Facebook contacts quick and simple. Your contacts are displayed in a list, and all you have to do is click one to start a conversation. The app also sends notifications to your device when you have received a message from one of your contacts.
The application is available on Android and iOS. If you use a computer, it doesn't require any installation; you will directly access to the Messenger website.