Just an idea:
nowdays you can choose if you want to open a topic or a poll.
a third thing would be handy like asking a question for specific answers.
If someone opens a new 'question', people will answer and the OP can mark the best answer in a checkbox next to the post. As soon as he mark a post as satisfactory answer for the question, the 'question topic' is automatically locked.
After this, the system can also open a new tab in the browser (if the OP has spendable merits), in order to help OP to give merit easily for the member who answered the question.
I was going to suggest exactly this. There are some forums which have already implemented something like this. This could reduce spam and would provide a better forum navigation.