This topic belongs to the more general discussion: What goes in the FAQ?
I'll make a start with the first FAQ section. Here is my proposal, following the FAQs of SO related sites:
What kind of questions can I ask here?
tex.stackexchange.com is for TeX and LaTeX enthusiasts and users. If you have a question about ...
- TeX or any of its descendants like LaTeX, XeTeX, LuaTeX and ConTeXt
- TeX distributions like TeX Live, MiKTeX or MacTeX,
- (La)TeX related software and tools like BibTeX, LyX, LaTeX editors, viewer and converter software
... then you're in the right place to ask your question!
The best questions contain some code. Their answers will most likely give concrete code back to you.
The FAQ continues:
Please look around to see if your question has already been asked (and maybe even answered!) before you ask...
I omitted the word 'expert', as I believe this site supports new users as well.
Further, I know that this site is not the perfect place for very specific questions regarding a certain editor or software. Though possibly help is available here because many of us use some of the common editors and tools. It might be hard for a new user to find the correct forum, mailing-list or wiki for a very specific piece of software. If a question is hard to answer here, we know where to lead the questioner as we know the resources. That's the reason why I included such related software: we don't sent the questioner back just because his question concerns a LaTeX IDE feature but not LaTeX itself.
Another FAQ entry or link could write that clearly. Remember the venn diagram on the about page: if the sets stand for TeX, LaTeX and friends: related software, then tex.stackexchange.com could be the tiny asterisk in the middle, their intersection.