When I figured out how to write Products easily, everything I wrote became a product. It was a simple and easy way of adding stuff into Zope.
Lets take an example, the python cookbook.
This site allows users to add in a recipe, which when approved goes live. Recipes can be commented on and rated. The actual code for reading in a new recipe, data checking is done in the external method. That external method is about 80 lines long. So where am I going with all this.