The way I see it, AskUbuntu despite being good for promoting friendly competition to increase answer range and quality through vanity rewards such as badges, shouldn't be tolerating this sort of methodology as it promotes speed answers rather than quality answers.
Either the user:
- Wants to inform the user that they'll have an answer soon in the case of hypothetical questions which need solving within a certain time-frame which is very rare.
In which case it would be better to post "I'm typing up an answer it will be completed soon." in the comment section below the question rather than a "please wait I'm writing the post..." in the answer section.
Or the user is doing it for reasons related to themselves:
1. Doing it to obtain various badges such as: Enlightened or Revival
Although in the case of the latter there wouldn't be much chance of other users posting an answer right before them if noone's answered in 30 days.
2. Making sure the answer they have worked towards gets the credit it deserves, in the case for example that another answer is written in the mean-time and the OP accepts without looking at theirs which could be of equal or higher standard.
3. They want to inform other people capable of answering the question that the question is already answered.
In case 1. Wanting to obtain badges:
The badges are a minor incentive and should be used as motivation to answer more questions rather than asking one question quickly. Quick answers will most of the time not lead to higher quality responses, in the case you've pointed out the answer was substantially improved, however this could not always be the case.
In case 2. They want credit for an answer they are researching/typing:
It is worth simply commenting and notifying the OP of the question afterwards regardless if someone else has already answered:
- Either the answers will be similar in which case they can add theirs as an edit and they will have contributed to making an even better answers together.
- Or they will be different solutions which will both benefit the community and the OP will be free to either accept their answer and/or upvote for effort.
In case 3. Wanting to inform others that the answer is already answered.
This is the worst case scenario in my opinion even though it could have stemmed from a good intention, doing this has several issues:
- The question comes up as already having an answer in the questions list reducing the chance people will give it a look.
- If the person writing the answer doesn't give a correct answer or one which doesn't solve the OP's problem, people will have overlooked it in the meantime despite potentially having more helpful ideas.
- The question may not get as many answers, taking an example of an unanswered question where 3 people work on finding a solution at the same time, they will post their solutions not knowing others are working on it and so provide 3 answers for the same question. If someone answers "Typing an answer now" 2 of those people could not bother and it would reduce the variety of answers obtained by the OP and maybe the quality too if the person posted an answer in a rush.
The counter-argument to the 3rd point of part 3. just above would be that:
"You could have 3 people typing exactly the same thing and it could waste time better spent answering other questions".
That could happen in which case you'd have 3 answers which confirm each other. However if you only had one person working on the question and they misunderstood the question or posted a solution which didn't work, then the OP wouldn't have any alternative answers to turn to, I view the case of sometimes having 3 answers confirming the same reasoning being a better option.
Disclaimer: This is but an opinion on the issue feel free to comment/counter-argument any points made, I could easily have missed something out/been completely wrong about something.