[willarson]

It probably is a good idea to flag the account as inactive, and move it to separate table to keep the primary table clean. AFAIK FaceBook won't know that you're not removing the data completely, and this will allow you to restore the user if they want to, but not bloat your app with outdated entries.

[bls]

If I find your application useless then I don't want you to retain any information about me.

[steve]

welcome to the internet.

[amichail]

What if you accidentally uninstall my app and lose many hours of work?

[bls]

I understand what you mean. But, who is going to be entering valuable, unreproducible data into Facebook? If they re-install your app then they will probably be pretty happy to enter everything all over again.