A while ago i found a website much like jsFiddle, focused on collaborative editing. It has forking and it's full of HTML5 experiments. Unfortunately i can't remember the name; do you by any chance ...
I searched so long for a opportunity where i can edit sourcecode with a friend or a co-worker together - collaborative editing. I found Gobby, Bespin (Skywriter) by Mozilla, Cloud9 IDE (at this time ...