pinax/django-announcements — pull request #22 by ntucker (2014-10-18 18:26:48+00:00)
Title: Support Django 1.5 configurable User model properly

Using the settings string is the official recommended way. using get_user_model() at the module level can potentially cause issues.

https://docs.djangoproject.com/en/1.7/topics/auth/customizing/#referencing-the-user-model