Nice! I like the social / dialogue aspect, though I probably prefer the interface of GLSL sandbox (
http://glsl.heroku.com/) and the way you can easily see how code has been derived through the parent / diff stuff. No textures / video though.
I was waiting for a program that will allow me to write shaders without changes in code,
Incidentally, if you're interested in an application that allows you to write shaders on the fly, then Praxis LIVE allows this (
http://youtu.be/19RIt9SslfY). It hasn't got syntax highlighting yet (coming soon!), but does allow you to work with whatever input (videos, textures, etc.) you want. And it's LWJGL based so tends to work faster than the in-browser stuff, at least for me.