It is not possible to order a Model on a field of the Model acting as the intermediate ‘through‘ of a ManyToMany relation in Django, because queries will not return items in the correct order, and in addition will include duplicate items, even when using .distinct().
This problem is current as of Django 1.3 and has no generic solution as far as I know.
When the optional ordering = … attribute of a model’s Meta class contains a GenericRelation from the Content Types framework in Django, there is no way to eliminate duplicate items being returned, even when using .distinct() (since .order_by(…) is applied by the ORM only after the SQL SELECT DISTINCT clause is built).
This problem is current as of Django 1.3 and has no generic solution as far as I know.