where interaction with mobile devices plays a central role (e.g. Making calls, checking messages, displaying content)

This is not restricted to software running on mobile devices (for such, rather use the corresponding tags such as , , or even more device specific , or ).

The mobile tag is more focused on cases where the software itself is not running on the mobile device itself. Examples include e.g. web-apps using responsive design, or controls to be used from mobile devices (which might also include Bluetooth, IrDa or WiFi).