First of all Cloud9 is a very good solution, they are the initial pioneers in cloud coding, and they built some good technology that we contribute to (and use small parts of).
We really try to focus on simplicity and extensibility.
We're trying a few different approaches, one of them being providing a whole network besides the code editor itself, so people can share plugins, build teams, find freelancers (that kind of stuff).
Cloud9 is very good, we're just about 6 months old and a two man team, so we're exploring things and trying to innovate.
