django-request is a statistics module for django. It stores requests in a database for admins to see, it can also be used to get statistics on who is online etc.
As well as a site statistics module, with the active_users template tag and manager method you can also use django-request to show who is online in a certain time.
Request.objects.active_users(minutes=15)
For a detailed documentation of django-request, or how to install django-request please see: django-request or the docs/ directory.