How should you answer a question that requires more information to be answerable on WikiAnswers?

That depends on what information is needed. If you can give a general answer, but need more specifics to narrow it down, then offer what you can. If there are a few different options, then give the options.

If the question is completely unanswerable because it lacks some essential bit of information, then flag it, or write to support @ answers.com, and we will take care of it for you.