Q:

Are there any ethical rules I am missing?

I am asking this question in order to improve my behavior on this site.
This question here: https://stackoverflow.com/q/38550962/982161
was answered by one user with good reputation but as 
community wiki, another good user (https://stackoverflow.com/users/1221571/eran) did the same but with no reason deleted the post, I did the same, answered the question correctly but got a down-vote.
Then after my analysis about this behavior: is there any kind of ethical rule that we should follow? I mean, if some good wiki answer is given, would I prefer to upvote this and abstain from writing my answer instead?

A:

First of all, I'm not sure why the answerer marked his answer as community wiki. I don't see how easy collaboration (the main advantage of a community wiki) could improve that answer. But, it is the author's choice and right to do so.
Especially seeing the timing of the posts (you were probably already typing when the CW answer was posted), it would have been perfectly reasonable to leave your answer there. In my opinion, the CW answer is better, as e.g. it briefly explains how the octal system works. Your post could use some better formatting and grammar, but otherwise it looks OK to me.
In any case, there is no ethical rule involved regarding Community Wiki posts (we do have rules against copying other answers, but that is clearly not the case here). In fact, if you have a structurally different answer than what's mentioned in the Community Wiki, you are encouraged to post it as another answer (rather than editing it in the CW answer). We do have rules against answering obviously duplicate questions - that might be a reason for the downvote, but we can never know for sure. The other deleted answer was deleted the same minute it was posted, so nobody got a chance at voting.

