Facebook Messenger is a stand-alone chat app that lets you to chat with your Facebook friends. The app is also expanding to support other third party apps so you can send GIFs and short movies in Messenger.
Chat with free voice and video calls
If you have a lot of Facebook friends, Messenger is the easiest way to keep in touch with them. Chats are normally one-on-one and you can see when your friend has read the message or when they are writing one. You can create group messages and have all your messages in one place.
Messenger also supports sharing photos and videos. You can take a photo or video directly in the app or attach a photo. If texting isn't enough, you can make free voice or video calls with the app. Both voice and video calls can be made through Wi-Fi or cellular data.
Messenger also gives you the option to share your location by default, which is good if you're meeting someone. The app also supports stickers by default and you can purchase more through Facebook's store. If you think the stickers are boring, you can download compatible apps for Messenger like GIFHY or Bitmoji to add a customized message.
There is also the possibility that games will be added to Messenger in the future.
Messenger on Android supports Chat Heads. Chat Heads are a persistent floating Messenger shortcut to your current conversations. You can move Chat Heads anywhere on your screen and it acts as an overlay on top of any running app. To close a Chat Head, hold the circle and swipe to the bottom of the screen.
Great when you use it, but it's easily forgotten
The usefulness of Messenger is based off how much you use it. If you talk to friends mainly through Messenger, the app is great. But if you use alternative messaging apps, Messenger can sit unused on your device.
But when you're traveling internationally, Messenger is a great app because you don't have to worry about expensive charges if you have to dial an international phone number.
Compatible apps for Messenger add more personalization, but don't dramatically change how you use the app. Messenger is first and foremost a chat app and it is great at connecting you to your friends.
However, Messenger will never replace your phone number or dialer even through Facebook is trying with Hello.
If you use Facebook, you need Messenger
Facebook is expanding the usability of Messenger slowly. It now supports voice and video calls and you can install compatible apps to add something extra to your chats.
But at its core, it's all about chatting with friends. And since messaging isn't supported in the main Facebook app, you're forced to use Messenger.