Edit: Now that we have some moderators, hopefully we can start moving towards getting a basic draft ready.
As you can see, our pages that list types on-topic is currently set to the default, which is not site specific. This post is for getting some ideas as to what this documentation should contain about what types of questions fall within the scope of this site. Your answer should look something like this (and this is copied from Super User's page):
Super User is for computer enthusiasts and power users. …
Specific issues with computer software, hardware or networking
Real problems or questions that you’ve encountered
Don't ask about...
Anything not directly related to computer software or computer hardware
Questions that are primarily opinion-based
Questions with too many possible answers or require an extremely long answer
Videogames, consoles, or other electronic devices, unless they connect to your computer
Websites or web services like Google, Facebook, Twitter, and WordPress
Shopping, buying or product recommendations
Issues specific to corporate IT support and networks
Make sure to include types of off-topic questions in your answer as well.