Question:Which login controls are useful only to authenticated users? 

Useful login controls to authenticate users:
1. CreateUserWizard
2. Login
3. Loginview
4. Loginstatus
5. Loginname
6. PasswordRecovery
7. ChangePassword

Question:What do data binding mean? 

With ASP.NET data binding, we can bind any server control to simple properties, collections, expressions and/or methods. We may use data binding to fill lists with selectable items from an imported data source, like a database, an XML file, or a script.