I've tried to retrieve the wmd-editor source tarball lately, but the site seems offline.

From what I've read on the Internet, wmd-editor is not (yet?) free software by itself, and its author has gone MIA.
But it looks like somebody recently took the step to rewrite a wmd-clone under a saner license, see [[pagedown|http://code.google.com/p/pagedown/source/browse/]].

Given all the above, what about upgrading this plugin to use pagedown instead of wmd? It seem a clear win to me...

> AFAICS, pagedown is a modified version of WMD. Let's 
> look at its license file: --[[Joey]] 

<pre>
A javascript port of Markdown, as used on Stack Overflow
and the rest of Stack Exchange network.

Largely based on showdown.js by John Fraser (Attacklab).

Original Markdown Copyright (c) 2004-2005 John Gruber
  <http://daringfireball.net/projects/markdown/>


Original Showdown code copyright (c) 2007 John Fraser

Modifications and bugfixes (c) 2009 Dana Robinson
Modifications and bugfixes (c) 2009-2011 Stack Exchange Inc.

Permission is hereby granted, free of charge, to any person obtaining a
copy [...]
</pre>

> Ok, so it says it's based on showdown. John Fraser wrote showdown and also 
> WMD, which IIRC was built on top of showdown. (Showdown converts the
> markdown to html, and WMD adds the editor UI.)
> 
> I can nowhere find a actual statement of the copyright of showdown or
> WMD. <http://code.google.com/p/wmd/> has a "MIT License" notice on it,
> but this is clearly just the license chosen when signing up at google
> code for the repo that would be used for a rewrite of the code, and the only thing 
> said about the previous 1.0 release of WMD is "use it freely", which is not
> specific enough to be a grant of license, and is moreover not a free
> software license, as it does not cover distribution or modification.
> 
> Which was all covered in the thread here, 
> when StackOverflow decided to start working on pagedown.
> <http://blog.stackoverflow.com/2008/12/reverse-engineering-the-wmd-editor/>
> This thread does not give any indication that they ever managed to get
> a license grant for WMD/showdown. It frankly, does not inspire confidence
> that the people working on this care about the license.
> 
> It would probably be pretty easy to adapt the ikiwiki wmd plugin 
> to use pagedown. But without a clear and credible license, why?
> 
> (Note that I have a wmd-new branch in my ikiwiki git repo that
> uses <https://github.com/derobins/wmd>, which was an earlier
> version of pagedown (probably, not entirely clear).)
> 
> An alternate alternative is markitup: <http://markitup.jaysalvat.com/>
> It has a clear history and a credible license (MIT or GPL dual license).
> It's also easily extensible to other formats so could handle rst etc.
> It does not, however, have a markdown to html converter -- for 
> previewing it has to talk to the server with AJAX.
> --[[Joey]]