dotneat.net

Yes, there is a bit of confusion about this (also read this post).

I understand that the right way to create your application specific exceptions classes is to inherit from Exception class:

public class MyCustomEx : System.Exception{
   //class implementation
}

And if in any case you have to throw a general application exception that has not specific type, throw a System.ApplicationException:

throw new System.ApplicationException("Error retrieving data. The web service may be down");