Probably we can have similar rating system like those in the wikipedia, in addition to the existing voting system. For each article inside wikipedia, reader can rate the article in term of trustworthy, objective, complete and well-written using a scale of 1 to 5.
In our case, each question and each answer will have a rating in term of the following:
 Completeness - Is the question / answer provided sufficient information? (Is the question clear enough? Is the answer completely answer the question?)
 Well-Written - Is the question / answer well-written? (Does it contain too many spelling errors?)
 Trustworthy - Does the links inside the question / answer workable? (Does the links provided point to wrong information or the very useful?)
The rating can also include a comment field in which user can provide how to improve the question / answer and it also add points to the user as describe below:
 For rating below 3, no points awarded
 For rating of 3, 1 or 2 points awarded
 For rating of 4, 3 or 4 points awarded
 For rating of 5, which is the best rating, 5 or 10 points awarded.
The points are awarded given that there are comment included.
Notice that the rating system did not deduct any points from user. Why? - the reason is simple - to encourage people to help each other and not shy away or scare of being deducted of points. It encourage active communication and help the whole community to evolve in a positive manner, thus building a warmly, active and positive community.
For your consideration. Suggestions and comments are warmly welcome.