Facebook today is launching Messenger, an Android and iOS app that "simplifies how messaging works."
From Facebook's blog:
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.
An extension of Facebook messages, this app consolidates all your channels of communication into one. It also allows you to communicate with groups as well as individuals. You can even add locations onto a map for others to view, and attach photos too.