<p>You are referring to a "Post notice."  These can be added to posts for various reasons:</p>

<ul>
<li><p>Citation needed</p>

<blockquote>
  <p>This post does not cite any references or sources. Please help improve this post by adding citations to reliable sources. Unsourced material may be challenged and removed.
  current event</p>
</blockquote></li>
<li><p>Post is related to a rapidly changing event.</p></li>
<li><p>Insufficient explanation</p>

<blockquote>
  <p>We're looking for long answers that provide some explanation and context. Don't just give a one-line answer; explain why your answer is right, ideally with citations. Answers that don't include explanations may be removed.</p>
</blockquote></li>
</ul>

<p>Only moderators can add these notices.  I added one to your original post because it was brief and telegraphic: it clearly did not meet our site standards and was at risk of being downvoted and even deleted.</p>

<p>When you amplified your answer, and I observed that you had done that, I removed the notice.  Unfortunately, there is no notification mechanism to let me (or other moderators) know that a change has been made to such an answer.  Consequently, you can still find a few answers on our site that now look great but still have post notices.  If you come across anything like that, then just flag it for moderator attention.</p>
