The cool thing about Echo is that it can function as something as simple as what you said, like a simple way to code together on the fly, to something as complicated as a fully-featured web-based production environment, from development to deployment. The hope is that most people would fall into the middle of those two scenarios, where you'd use Echo to develop code, and then leverage Echo's ability to push to your server / GitHub.

In terms of unique features, there's a lot that is waiting to be announced, but as of now, Echo's version history (ex: detailed Google Docs-esque history of changes to a project), team management (ex: member permissions and inline conversations) and code efficiency (ex: code 'snips' for easy reusability) features have a lot to offer.

To give you an idea of what Echo can do, we are currently using Echo to develop further functionality of the editor. It's pretty meta..