Facebook knows it has to play the ad card carefully, so our main concern here is how it will work out what type of messages you might want or not want to see in Messenger. We are unable to comment further until Facebook reveals - assuming it will - Messenger ads.
Why does Facebook Messenger need access to your camera?
If you want to send a photo to a friend directly through the Messenger app, you'll be asked to give permission for the app to access your camera. It's not asking you to let it access the camera so that it can watch you while you're sleeping.
Why does Facebook Messenger need access to your microphone?
If you want to voice call a friend through Facebook Messenger, the app will need permission to access your microphone, because otherwise it wouldn't be able to hear what you're saying and neither would your friend. The microphone is also required for recording and sending video clips with audio.
Can Facebook Messenger call my contacts without my knowledge?
You'll need to give Facebook Messenger permission to directly call phone numbers if you want to use the app, but it won't do so without your knowledge. What the permission actually does is allow you to call a Messenger contact by tapping on their phone number.
Can Facebook Messenger text my contacts without my knowledge?
Facebook also requires permission to edit, receive, read and send SMS messages, which is understandably confusing, but you can rest assured that the company isn't going to send your friends messages without your permission. The app needs you to allow it to have control over messages to allow you to confirm your phone number via a confirmation code that Facebook sends to you via text message.
Giving Facebook Messenger permission to read your contacts will let you add the contacts stored on your device as Messenger contacts if you want to.
It does seem more daunting when you're asked to give these permissions on Android because you'll be shown all of the possible permissions that Facebook Messenger needs at once without an explanation of what giving those permissions to the app will enable you to achieve. It's slightly different on iOS, because you'll be asked to give these permissions one at a time when you use various features available in the app.
"Almost all apps need permission to run on Android, and we use these permissions to run features in the app," writes Facebook in a blog post explaining why the Messenger app requests permission to access features on Android. "Keep in mind that Android controls the way the permissions are named, and the way they're named doesn't necessarily reflect the way the Messenger app and other apps use them."
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