Facebook doesn't run GPS in the background unless you give us permission by turning on optional features that require this. To make our app better for you, we bring updates to the App Store regularly.
Every update of our Facebook app includes improvements for speed and reliability.
If you are using an application to be logged into facebook, facebook will know that you are using it on mobile and place the icon.
If you are updating your facebook status via sms, then also facebook will know and place the icon.
Facebook's Messenger app will stop working for a number of smartphone users by the end of March.This works perfectly when I update my FB status using a computer.However, when the update is done via mobile device, it is only visible to my FB friends, not to everyone as originally intended.When I logon to FB via a computer, I can see there is a padlock icon after my mobile update.The icon is not there when I update the status via the computer. The "padlock" icon after a mobile update occurs when you update your status from a mobile. If you want it to not appear, you should be logged on to your mobile and see facebook in its real form instead of m.