Like every online community going back to the days before WWW, in order to get the most out of a community like ServerFault, you have to put in some time and effort to figure out how it works. If you don't put in any time, you might still get some benefit from the community, but on the other hand you might find that it doesn't work for you at all.
Some threads such as superuser and serverfault are very nearby and difference is so small, so you always think where you should post. And there no place to check this. So I have down votes only because I put my question under different thread.
If you look at the FAQs for SF and SU, they make it pretty clear what's appropriate for each site. They also make it clear what types of question are suited to these sites and what types are not. Questions that require a lengthy, guidebook-style answer are one of the type that are not appropriate.