Post Notices can be added to a post by moderators. These are predefined. Moderators cannot add their own text. Post Notices appear below the posts until removed manually.

Currently, Stack Overflow moderators can pick the following:

* **citation needed**: 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**: Post is related to a rapidly changing event.

* **insufficient explanation**: 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.

* **redditted**: Welcome, Redditors! We're looking for answers that provide serious, practical solutions to the problem stated. If you'd prefer to post a joke or launch a tangential discussion, please do so on the corresponding Reddit thread.


This is how it looks like in the UI:

![post notices][1]

Related information on meta.SE:

- https://meta.stackexchange.com/questions/165006/what-are-these-notices-under-my-post
- https://meta.stackexchange.com/questions/172571/how-rare-should-post-notices-be
- http://blog.stackoverflow.com/2011/09/bounty-reasons-and-post-notices/

As for the reddited one:

The **reddited** post notice came into existence after [this question][2] somehow made it to the [Reddit][3] frontpage. It resulted in lots and lots of joke answers and comments on that question, which we deleted, which then created complaints on MSO. So [@shog9 added the notice][4] to handle this:

> I created that notice for a question earlier today. I did so after deleting a half-dozen or so "answers" that, while perhaps somewhat clever, didn't bother trying to actually answer the question.


  [1]: https://i.sstatic.net/cRLcM.png
  [2]: http://stackoverflow.com/questions/14415881/how-to-pair-socks-from-a-pile-efficiently
  [3]: http://www.reddit.com/r/programming/comments/16x9a3/how_to_pair_socks_from_a_pile_efficiently/?sort=old
  [4]: http://www.reddit.com/r/programming/comments/16y0as/til_that_redditors_going_to_stack_overflow_and/c80j92e