In my experience as a user of stack exchange sites, I have seen that some users who try to answer question want to complete an existing answer to a question or they want to share their own experience related to some points of an existing answer. Also, some users want to develop or extend the existing feature of an answer however, they do not really want to separately post an answer to a question. Their posts are not as complete as answers but they are not comments too. These are something between a complete answer and a comment to it.

These type of answers are usually followed by a structure like: `the answer by user A perfectly answers this question, but I want to add my own experience....` or some other who want to complete an existing answer and build their answers upon an existing point (such as a programming code) post answers like: `I am making this program code upon user A's answer and want to add this minor feature to it...`.

So, we see that some answers are built upon existing answers to questions.

I think that the websites lack a feature like posting **Sub-Answers** which may allow the users to post answers as a sub category or sub-post to existing answers. By having this feature, these answers are organized under the answer which they are completing or extending it. Also, when the question is opened and the answers are sorted by number of votes or newest answer, the answers and their sub-answers are shown together so other users may not lose the connection between answers.

Here is a the sample structure of this feature:

```
Question's Title
Question's Text

Answer 1
Comments on Answer 1

Answer 2
Comments on Answer 2

     Sub-Answer 2-1
     Comments on Sub-Answer 2-1

     Sub-Answer 2-2
     Comments on Sub-Answer 2-2

```