There is an answer to a previous question that forms a possible answer to this question, but I want to come back to the root cause of the problem of users not choosing or accepting an answer to questions.
Do users also know that they gain some XP for accepting answers?
Are we doing enough to encourage them to do so and thus making each Q&A more complete?
I feel like it is good to try and get to the bottom of this because there is a mutual benefit for the person posting the question and the people who answer them, not to mention the rest of the community that then reads the entry at a future date.
So how can we encourage users to accept an answer to a question? Can/Should a similar system/interaction/behaviour for bounties be implemented?