Is there a difference between the social networking you do online and the interactivity that takes place through text messages and real-time online chatting? If there is, the new Facebook Messenger app for Android will immediately make sense to you. Others, on the other hand, will see it as a needless second app that largely duplicates select features of the original Facebook for Android app (free, 3.5 stars). Facebook Messenger, which was developed by Facebook itself, compartmentalizes the more immediate activities of