Actually it looks like the whole lilypond.org/web/* is out of date and
deprecated; is there actually a reason to risk confusing potential users of
Lilypond?
Well yes if you read the bug trackers.
In a nutshell (and with my limited knowledge) the website is built not
by humans but by machine (so to speak) at least a large chunk is
anyway; so you have to make sure you are not going to break something
when the 'scripts' that build the website no longer find that
directory that 'you' have just moved or the file you have just edited
no longer references a .png and now the whole website is broken.
It isn't just someone poking about with some HTML code in a text
editor - at least from doing documentation for LP that's as I have
come to understand it.
As it says here:
http://lilypond.org/doc/v2.15/Documentation/contributor/introduction-to-website-work
'The website is not written directly in HTML; instead, the source is
Texinfo, which is then
generated into HTML, PDF, and Info formats.
As has been said, any help is welcome and there are people on the
lists who can help or advise to those that want to help.
Take a look:
http://code.google.com/p/lilypond/issues/list?can=2&q=website&colspec=ID&groupby=&sort=priority&x=type&y=priority&cells=tiles&mode=grid
Lots to do :)