Why use Visual Basic? The Microsoft Visual Basic programming system allows you to create attractive and effective graphical user interfaces (GUI) tailored to meet the specific needs of your ArcView application.
By integrating Visual Basic with ArcView, you exploit the rich toolset Visual Basic provides and create custom dialog boxes that would be difficult to create with Avenue alone. For example, you might use Visual Basic to create an interface to access functionality contained in an Avenue script.
For detailed information on DDE please access the ArcView Help topic "DDE" from the Index tab.