The product types are to products, what content types are to simple Drupal content like Articles.
- The membership product type includes (in addition to the fields of a standard product) a list of selectable options displayed as radio buttons, one of which is required.
- The conference product type also includes the membership level field that was created for the membership product type (remember, fields can be reused in different content types). But it also includes a conference body field (long text field), and a conference participation field (a long list of radio button options).
- The conference meal product type includes a meal body field and a lunch option select list.
Each of these content types has a unique body field so that the field can be used as feedback to the user when one of the select list options is chosen on the product display page.