Content classes are used to define the structure of your content. Content objects are instances of the content class definition.

The ability to create your own content types can be better exemplified by looking at a particular example. I believe most readers can infer the possibilities of creating your own content types with an example of how a stock class such as "Article" can be extended.

The stock Article class that comes out of the box with a lot of the sample sites includes the basics of what you would need in an Article class. It has a Name, a Summary (for displaying a teaser line), the Article text itself, an image, an author.

eZpublish lets you easily take a custom Article requirement such as "download link for a diagram file with each article". To do this you would simply go to the administrative interface and "Edit" the class "Article" and add a "File" attribute.

Some of the built-in attribute types go beyond the simple "input field", "file", "url" kinds of fields, but also allow the class editor to specify object relationships with a navigating mechanism to allow association of objects for complex content structures.