Although people typically install it on their phones to chat privately with their Facebook friends, Facebook also uses Messenger to bring features and capabilities that might not make sense, or even be possible, as part of the main Facebook service. And of course, a separate app gives Facebook even more advertising and other moneymaking opportunities.
For that reason, Facebook is pushing users to download the app, even though it takes up valuable storage on the phone. The company recently started blocking access to Facebook messages from mobile web browsers on Android phones in some markets. The ban will extend to iPhones as well, though Facebook isn't saying when.
Before you complain, consider what a separate Messenger app offers beyond simply typing words and sending emoji back and forth:
1. Group chats
Messenger lets you easily add friends to group chats so you can make dinner or travel plans or just talk about your day. Although this is also possible using your browser, it's more convenient with the app. If kicking people off mobile browser messaging is the stick to prod people toward the app, the convenience of Messenger is the carrot to lure users.
Tapping the "groups" icon at the bottom of the screen will take you to existing group chats and let you start new ones. You can add people to group chats at any time, or leave the group. If you have an often-used group chat, you can also "pin" it to the top of your messages to make it easily accessible.
Who wants to chat with people when you can chat with ... bots? Well, most of us, but bear with me here.
Since April, Facebook has let outside businesses create "chat bots" that can send you the news or weather, help you shop for shoes or book plane tickets and hotel rooms. You send a message to a brand's bot just as you would a friend; the difference is that the reply is automated through software. The results can be clumsy, as expected for such a new venture.
But bots can be helpful. Expedia, for example, lets you search for hotels and book them by messaging with its bot. Start by telling the bot where you are going and when. After some back and forth, the bot will give you hotel options. To book, the bot will take you to Expedia's website.
This is just the start. Perhaps one day, the bot will be more useful by letting you book directly through Messenger. David Marcus, Facebook's head of messaging products, has called bots "overhyped in the short term and underhyped in the long term."
3. Send or request money
Using your debit card, you can send money to your Facebook friends using Messenger - as long as they also have their card number attached to their Facebook account. You can also request money, in case your friends forgot to pay you for those movie tickets and aren't answering their email. To use the payments option, select the person you want money from and tap "payments." There are no extra fees to send or receive payments, but you must use a debit card - not a credit card.
4. Video calls
Your mom isn't on Skype? FaceTime isn't cutting it because your friend has Android?
Messenger offers yet another way to do video calls on your phone. It's free over a Wi-Fi connection. If you use cellular, you might get charged for data by your phone company.
5. Play games
How about some soccer - or football, as it's known in most of the world? Select a friend to play with. Then, select Messenger's emoji keyboard by tapping on the emoji icon on the left side of your message window, right above the keyboard. Tap the soccer ball icon and send it to your friend. Then, tap the ball with your finger and keep tapping it so it stays in the "air."
During a recent, frustrating attempt, I had a high score of just two - though that's still one more than what Portugal scored to win the Euro Cup this year.