Facebook is sending out mails like this to app developers:
In short, if you don't provide a privacy policy for your Facebook app, you're risking deactivation.
Notice of Violation: Privacy Policy
Hi,
We’ve found the following policy violation with your app and you need to address this issue by Tuesday April 22, 2012 at 2:00pm PST or your app may be subject to enforcement action.
Our policies require that your app has a privacy policy that tells users what user data you are going to use and how you will use, display, share, or transfer that data and you will include your privacy policy URL in the Developer Application (See Platform Policy II.3, http://developers.facebook.com/policy).
It has come to our attention that your app is missing a privacy policy in the permissions dialogue. Please update the privacy policy URL field in the Developer Application at developers.facebook.com/apps/[YOUR_APP_ID]/auth. Also, please review your app to ensure you are also displaying your privacy policy on your web site or within your app.
Thanks,
Platform Policy Team