Here are some features of the messenger platform that facebook painstakingly built.
Now you can mention someone in the conversation and he/she can reply to it with @username.
Live Location Sharing
This one is very similar to what apple has been doing with its iMessage since long back but nevertheless its here on Messenger.Press on the Gps icon from where you can share your location.
This once is really good as facebook globally connected platform means your friends are just a reach away.Tap video camera and start calling your friends right away.
Tap the middle button to snap selfies or select few pics doodle over them and express yourself with friends and family.Oh,and this just lasts for a day.