Updated 2008-02-26: changed the syntax a little

Logical grouping / DIV syntax for Markdown

+-- starts a div, =-- ends a div (both with up to 3 indentation):

+--
  Inside a div..
=--

DIVs can be nested:

+--
Inside first DIV
 +--
  DIV inside DIV
 =--
=--

Attribute lists can be put after +-- or after ---:

+--                           {.warning}
This is a Warning!
=--

+--
Second Warning!
=--                           {.warning}

Compressed syntax: if the first line after +-- begins with |, the content of the DIV is anything following beginning with |.

+--                           {.warning}
| third 
| warning!

In this case, a final +---- line can be added for visual candy:

+--                           {.warning}
| third 
| warning!
+--------------

Example nesting and attributes:

+-----------------------------------{.warning}------
| this is the last warning!
|
| please, go away!
|
|+------------------------------------- {.menace} --
|| or else terrible things will happen
|+--------------------------------------------------
+---------------------------------------------------

this translates to:

<div class="warning">
  <p>this is the last warning!</p>
  <p>please, go away!</p>
  <div class="menace">
  <p>or else terrible things will happen</p>
  </div>
</div>