In what criteria/criterion should we use the community wiki for questions?
What should it not be used for and what is a good example of it's use?
There are almost no situations where a question should be made a community wiki and it still be a good fit for our QA format.
Grace Note, in a blog entry, stated (emphasis not mine, it's literally bold in the post)
questions rarely, if ever, need community wiki.
And while answers are often legitimate candidates for community wiki, if a question solicits answers that are likely candidates for community wiki, the question itself was probably not a good fit for our format in the first place.
I don't think we should use it at all. I think questions that should be CW are probably not constructive in the first place and should either be rewritten or avoided entirely. List questions, shopping questions, and other questions that are tempting for a CW are usually poor quality and in need of an edit. They seldom have lasting value to either the community or the drive by user.
I have to disagree, there are a lot of great CW questions on StackOverflow that contain interesting information. I would admit that it would put more emphasis on moderation (to weed out answers that do not comply with the FAQ) but still it's not a good reason to omit them altogether.
EDIT: I see the points raised by @Grace Note, in the linked blog entry and realize that it's shaky grounds, but I still think it could be a useful holder for content.
EDIT2: Since my point is apparently not going through I will just post some links to some good (useful) questions in wiki form:
I would like to remind that rules and regulations are implemented and followed in social environments to improve and ensure everyone's experience in the medium, not for the sake of following rules. FAQ much like any other rule system (even constitutions of countries) change over time. If community wikis, or any other form of information exchange for that matter, prove to enhance the quality and quantity of the knowledge put here, it's worth considering.