Your encrypted data will be safe on the Project XIII servers. All data is moved between friends in an encrypted state. The data is stored for three days and then permanently deleted. During this three day window your friends can download your updates, messages, comments, etc.
Please remember your password! It cannot be reset by the server team. So please make sure to remember your password or write it down in a safe place.
Notifications are used by the Windows Phone. You have the option of turning them on or off. Please make sure that you understand any charges that this may incur with your provider.