"Messages has always been the place for private exchanges on Facebook, and this won’t change. With the new Messages, now you have easy access to all your private conversations with your friends in one place.
The new Messages interface not only displays the Facebook messages you exchange with friends, but it also interweaves your chats, texts and emails (should you choose to create an @facebook.com address). It’s a central place to control all of your private communication, both on and off Facebook.
Now when you view a conversation, you’re actually looking at a complete history of all the communication you’ve shared with that person on Facebook — it’s like having an ongoing record of your friendship."
Faster interaction: If you want, you can send messages just by hitting your Enter key, so the new Messages is as fast (and as informal) as an in-person conversation.
Integrated communication: No matter what you’re using to communicate (Facebook, mobile or email), your conversation streams quickly and seamlessly into one place.
Smart filtering: You’ll always see what’s important to you first – messages from the people you’re close to take precedence over mailing lists.
Revamped search: Search for either the person you were talking with or what you were talking about to quickly find your message and all the related context.
Adding people to group conversations
Unsubscribing, or removing yourself from a conversation
Regardless of your thoughts on the Facebook messages platform, we all want an invite to test it out!!
To request an invite, visit Facebook's Messages Page and click on request.