Seems like the same basic issue as http://meta.ubuntu.stackexchange.com/questions/47/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 point the user to /*etc/apache2/sites-{available,enabled}/* or */etc/apache2/mods-{available,enabled}/* feels rather specific enough 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 serverfault.