# Hidden Features of Stack Exchange

Not all features of Stack Exchange are very visible, and reading/editing as many posts as I have been, I have observed that many users seem to be missing out on some features.

So let us collect the more hidden features here for future referencing convenience.

• has anyone heard of a way to look at edit activity across the site including comments? the standard sorting on the main page seems to be by last edit time but excluding comment editing. do any of the moderator tools support that? – vzn Sep 5 '12 at 15:11
• Hidden features are not mentioned in the FAQ and the editing help, right? – Martin Schröder Nov 21 '12 at 9:25
• Arguably, the editing help is kind of hidden. Many new users don't look there, an man old ones don't either (so they miss changes). But then, new users at least won't look at this post either, unless we link it often in comments. – Raphael Nov 22 '12 at 10:22

You can define new LaTeX commands which can be used for the rest of the post. For example,

Lorem ipsum.$\newcommand{\nats}{\mathbb{N}}$

For $a \in \nats$, lorem ipsum.


becomes

See here for a real-life example.

If you want to hide something unless the user mouses over (to use as a hint):

Stop mouseovering me!

This is known as spoiler markup. It is achieved by putting >! at the front of a paragraph. Only a single, whole paragraph can be hidden in this way.

>! Stop mouseovering me!


Credit goes to the users (including @Raphael) already doing this. :P

• For the record, this can indeed be found in the Markdown help accessible via the question mark in the post editor, and "help" next to comment input boxes. – Raphael Nov 5 '12 at 12:06

We can typeset mathematics in (a subset of) LaTeX. See here for details.

• That's not exactly a hidden feature: It's explained in the editing help. – Martin Schröder Nov 21 '12 at 9:24

Comments allow a restricted set of Markdown. So, for instance, links can be used:

Crossposted on [math.SE](long URL).


or similar is preferred over pasting the naked URL to a question or website.

There are also some extra features not available in proper posts, namely shortcuts to special sites. For example,

We should discuss on [meta] or in [chat] whether this question would be better off on [so] or [math.se].


is expanded to contain proper links to the sites and their full names as link texts.

And, maybe most importantly, you can @-notify other commenters. Otherwise the people you talk to may never realise you answered them! For example, if you responded to one of my comments, you would start with @Raphael to send me a notification so I can read and act upon your comment.

Every post's complete version history is accessible via the link "edited [date and time]" next to the author's avatar. You can inspect the changes users have made and roll back to earlier revisions (use with care!).

We have a chat with persistent history. If you have any question about or problem with anything related to the site or CS in general, you can go there. Even if nobody is there at the time, people can answer and @-notify you later; you then get a notification similar to comment answers on the main site.