Facebook released a separate messaging app for iPhone and Android devices today.
Those who are heavy users of the service will likely appreciate no longer needing to navigate through the main Facebook app to get to retrieve and respond to messages. However, for casual users it may be redundant to have both apps on their device.
By default Facebook Messenger shares your location with every message. If you do not want to notify the recipient of your specific GPS coordinates, tap the icon to turn this off.
Alerts by default are also always on. They can be paused for an hour or overnight until 8:00 am. Fortunately, it appears that installing the Facebook Messenger app does not mean notifications from both Facebook apps when a message arrives.
A push notice will notify users of incoming messages, playing the same sound as the desktop chat service.