Mark a comment as answer to a question
I find that in many cases a comment I've made turns out to be the answer to the question. I suggest adding a "convert-comment-to-answer" button.
If it is a comment, it is too short for an answer.
You can easily click the
edit link next to your comment, copy to an answer and improve/flesh out before posting, then deleting the comment.
Most of the times, comment doesn't fit as an answer, because comments are too short.
Sometimes it would be useful, though
However, I do not think this would ever become status-completed, because it's too simple to just copy your comment and put it as an answer instead