Seems like the same basic issue as How do we tell if a question belongs here, or rather at stackoverflow/superuser?
It simply depends on the question.
Any basic question where the answer involves pointing the user to /etc/apache2/sites-{available,enabled}/ or /etc/apache2/mods-{available,enabled}/ certainly feels relevant for this site. On the other hand, to continue with an Apache example, a question comparing the benefits of different MPM:s (prefork, worker, etc) might do better at Server Fault.
