This app attempts to provide a generic category system that multiple apps could use. It uses MPTT for the tree storage and provides a custom admin for better visualization (copied and modified from feinCMS).
In the Django Authentication package is that all users use the same model/profile. This can be a drawback if you have lots of users or you want different information stored for your staff members, such as bio, contact info, etc. It is also handy for linking to models for author fields so the lookup is quicker.