I'm the maintainer for Google Code Prettify.

Markup authors can specify the language for source code, but not markdown authors.
Are the SO admins interested in a way of doing this?

If so, might the following work


If the first line is "#!" followed by one or more word characters, then make the first line invisible (using CSS hidden:visible) and use those word characters as the file extension.
Otherwise, use the current scheme.


So

#!css
tag.class#id { color: red }


would be recognized as CSS.

In markdown, should any indicator of line numbers survive copy-paste in markdown?

Does any scheme like this need to do work to handle quoting of responses in markdown?  Is it common for inline responders to split code sections?

Do users also want to number lines ( http://google-code-prettify.googlecode.com/svn/trunk/README.html#linenums ), so that others can respond with reference to particular lines?


Question: How did they start sending messages to other's phone?
Answer: 
  When the anime starts and until episode 8, they attached a cell-phone
  to the phone-microwave and sent a message to that specific phone to
  trigger sending D-Mails.


You are misunderstanding it. The microwave is required to send the d-mail, not to receive it. 

Basically, the d-mail functions exactly as a normal text message that you would send to someone. The only difference (apart from the size limit) is that when you send a normal message, it will arrive in some time after being sent. The d-mail, on the contrary, will arrive in some time before being sent. It can be sent to any phone (or a pager), the only requirement is obviously that you need to know the phone number.

As for your side question, I didn't understand what exactly is confusing you, can you elaborate please?