In a nut shell, it allows you to send messages from your Android device to another Android device. Big whoop eh? There's loads of messaging apps out there that do that, right? You, kind Sir/Madam are indeed correct, however there are no messaging apps that do it, the way Uooka Flash Messenger does it.
Uooka encrypts your message using military grade encryption software (PKE) that encrypts your message before it sends it. And now here's the fun part, only the person who the encrypted message is intended for can open it. Only they can open it because when you install Uooka Flash Messenger, it's creates a cryptographic key on your Android device and only on your Android device. This key is stored nowhere else and it is needed to decrypt the message.
So let's say while your message is in transit, a very rich/scary man comes to our offices and tells us that if we let/don't let him read the message you just sent they will give us $1 million/a nice set of concrete shoes. Well, unfortunately we would have to decline both offers, because we don't have the key required to decrypt the message. We don't have it because it only exists, where? Yep you guessed it, on your device.
And now here's the flash part, see I told you I would get there eventually. To enhance security, none of the messages you send or receive are stored on your device. You send a message, and it's gone. You receive a message and once you reply, the message thread is gone. Our thinking is "Hey stop touching my stuff/reading my messages". So unless you can read my mind my messages are safe, "Hey stop reading my mind".