The principal reason for not allowing a user to change the best answer is to prevent abuse of the accolade award for best answers. For example, if we allowed users to change the best answer on their question multiple times, then people could quickly get the "1,000 Best Answers" accolade without actually earning it.
It's possible that we will allow users to change the best answer at a later date, but it will require some care in order to prevent abuse.
Our species being what it is... If you let people "abuse" the accolade, you will get a frenzy of answers 5 times more than what it would otherwise be. And each of those answers, by necessity (if it wants to be selected as the new best answer), would have to be better than all the previous answers. This would all be a good thing.
As for the "you select mine and I'll select yours" crowd, just shoot them.
That's my tentative theory; but it probably needs some work...
Anyway the accolades don't give hubbers any incentives other than psychological happiness. So, developments shouldn't be hindered just because a few may misuse the feature. PD and ngureco do have good suggestions and I agree.
1. Give the best answerer a 20% of the impressions as an incentive to provide good answers, and in which case answers in the form of hubs should not qualify as they already get a 60% of impression.
2. Once the answer is selected as Best Answer it will move right below the Question and appear highlighted. Give an extra ad block there as an incentive so that those with thousands of answers can go back and pick on the best answers.
3. When one asks a question, its natural he/she doesn’t know the best answer. They may need help from volunteer hubbers.
Regarding (1). The staff have indeed talked about incentivizing best answers via sharing advertising revenue. While we might implement that feature in the future, we first wanted to see what kind of effect a "best answer" feature has without it.
Regarding (3). I believe that we already provide two mechanisms for the community to recommend a best answer: voting and commenting on answers.
Let's say I award best answers 98% of the time... maybe on all my questions, it could say something like, "98% accept rate."
That way when people come across my questions, they're like, "Oh hey, this person awards best answers a lot. I shall put forth some effort and answer this question."
I see this method used on StackOverFlow. It gives users a reason to come back and look over their questions and award answers... since people are more likely to respond to questions with high accept rates.
This way you would be rewarding both those who answer questions (via the "best answer") and those who ask the questions (giving them accept rates thus increasing the chance people will answer their questions.)
Example since I'm terribad at explaining things:
Edit: I was thinking. I think it would work out the best if the % was based on questions that have answers, not all questions a user has asked. It would be unfair to have a low percentage simply because many of your questions have gone unanswered.
I just used this new feature on a couple of my questions and I love it. I find that some people don't answer questions properly. They either don't understand the question or they go off on a tangent and start talking about something else.
Now, with the "best answer feature" I can also go ahead and mark one specific answer when I see that they have directly answered my question. Whether I agree or not makes no difference. Staying on topic and referencing the question that's asked is all I'm looking for to decide on a best answer.
Hmmmmmm - are there going to be some guidelines about this? Should we always award best answer? Is there a down side not to awarding? What if a best answer turns out to be factually incorrect? What about when 'something new' comes along that makes the best answer wrong?
As an example I might ask "What is the best e-reader?" get 20 answers and award the best answer to someone who writes a detailed answer about the iPad - then Amazon may bring out a new product that is simply 10 times better - I would want to be able to re-award a best answer.
Perhaps we can have an option to change the best answer, but this has to be moderated -so that there is no abuse of the accolade system? - sorry for the extra work I may be giving the moderation team!
I like the idea of rewarding strong answers - just one question - do you think it will inhibit traffic if the 'best' has already been selected? I'm not sure how those things work (traffic-wise); just wanted to ask and learn more.
It's amazing to see all the new features you are launching!