For karma, I'd recommend that each person gets points in proportion to the number of upvotes combined with the number of characters they added to an answer that appear in the final answer.
Also, I think you need some sort of comparison or overview for each issue. And next to the pie chart I think you should allow for a 140 character final recommendation, listed individually for each user. E.g., "Dan recommends SilkJS because it's easy to write, fast, and better than Node"