Kompozer Filgood sent me an e-mail this weekend, telling me about Noteflight, and how he used in on Kompoz. 

Noteflight is a tool that lets people create and share scores (written music) online with others.  The Noteflight Score Editor is a full-featured application that displays, edits, prints and plays back music notation in any standard web browser.

Philippe used it to embed a score as a comment to the Kompoz project It's All Gone.  What's cool about this embedded score is that -- not only can you view it -- you can also play it!