By default, the expression Yii::app()->user returns a CWebUser application component which represents the information that are closely related with the current user. Some information can be persistent throughout the current user session. For example, CWebUser already comes with a name property that stores the username of the current user.
This little tutorial explains a way how you can retrieve more parameters from Yii::app()->user by adding a component that extends CWebUser and retrieves the user information from database table named User.
These features provide endless possibilities and unbelievable flexibility, but as current documentation does not give more than a few examples, it might be difficult to fully understand their internals and requirements.
CGridView (or CListView) together with CActiveDataProvider is a very powerful combination of the built-in tools of Yii. But how do they work together to accomplish their fantastic functions? And what are you expected to do to use them and to customize their behaviors? This article explains the very basics of them.