Probably millions ! The system suggests categories according to the wording of the question. Sometimes that may result in the question being posted in the wrong section, and needs recategorizing.
As of August 13, 2013, there are 19,591,633 questions that have been answered on WikiAnswers.
Infinite
There are many thousands of unanswered questions, on hundreds of topics on WikiAnswers - fortunately this is no longer one of them !
There are over 600 questions about Michelangelo on WikiAnswers.
There are over 224,500 questions about celebrities on WikiAnswers.
There are over 1,000 athlete questions on WikiAnswers.
There are over 6,500 questions about authors on WikiAnswers.
There are over 6,500 questions about poets on WikiAnswers.
4,622 and counting
There are over 20,000 questions about entertainment and arts questions on WikiAnswers.
Yes, you can ask as many questions as you want on WikiAnswers. Also, it never hurts to ask/answer many questions also.
There are over 10,000 questions about drama and acting on WikiAnswers.