Asterisk is a Server-based VOIP Phone system that is usually run on Linux, and usually run on a network. I have seen posts for Asterisk in ServerFault, StackOverflow, and SuperUser. I even saw one post somewhere in those sites (sorry, I can't remember where and cannot find it in my history) where there was a debate about whether the user's Asterisk question ought to be posted in SuperUser or ServerFault.
Here is an Asterisk question migrated from SuperUser to ServerFault.
Here is a comment on StackOverflow, by a rep of 635 where the user was told his question would be better asked on SuperUser or ServerFault.
Hence, my question, what is the most relevant Q&A site for this, ServerFault, StackOverflow, or SuperUser?