CodePen is a service which went into public beta today. The founders are Chris Coyier, Alex Vazquez and Tim Sabat. It’s kind of like jsfiddle, but with a social touch. This could turn out to be really cool.
Biggest problem for me at the moment is, that I really don’t like the design. But let’s see how Codepen evolves. You can find my profile here: http://codepen.io/martinwolf