One of the changes I've wanted to put in place was the ability to backup a users data in the cloud. At first I was thinking of storing the entire data model in a NoSQL solution. I wasn't sure between Google's or Amazon's implementation I would adopt. I really didn't know much about either option. 

I think that maybe I should just store the XML data file I create today in one of the solutions available. I figured I'd need a unique I'd for each user to make it easier to identify their data.  The problem I've come up with since is that I'm not sure how to keep that unique ID as users move from device to device or reinstall to a device.

I'm tempted to start asking for use of their gmail account but I know that solution has flaws. What if people don't want to allow me access to their account? What if people don't care about their google account and just create a new one when they upgrade. I don't want to force people to provide an account to use my app.

What I've discovered is that there is a simple backup option in Android for users with 2.2 and up phones.  I've successfully generated a UUID for an install and backed it up with the app preferences.  This feature will be something I roll out on the paid version of the app.