This is definitely a huge plus point in any instant messaging app for sure, since there are moments when you actually sent a message to a wrong person, or sent the wrong message to the right person, either way, you can recall that message, even if it has already been read. Maintaining a message log is no longer all that watertight in an argument if one can recall messages though, especially between feuding couples or friends.
The updated Samsung ChatOn app will be able to support file transfers of up to 1GB as well, which will be limited to 5 transfers per day per user, and you can also attach your current location data to messages using Glympse. Does this give you reason to download and install Samsung ChatOn on your Android device?