I found this nice suggestion by Janek in the archives: http://lists.gnu.org/archive/html/bug-lilypond/2013-07/msg00038.html

The main purpose is encouraging new users to try lilypond before installing anything. A simple way could be adding a prominent link to tunefl/lilybin live preview.

Even better, creating an interactive tutorial similar to these:

http://tryhaskell.org/ http://try.github.io/levels/1/challenges/1

This requires javascript.. don't know how the developers team would feel about it. Currently the javascript used is almost nothing (just google analytics and the pondings).

Perhaps someone will create a website for this sort of things and we'll add a link to it.. I'm adding the idea here so that it doesn't get lost.

I would "donate" a subdomain of openlilylib.org for such a project, but I can't maintain it. I can't promise it will be "eternally" available, but maybe it is better than nothing.