I see web-based IDEs as potentially becoming a big thing in corporate enterprise world. I've worked in environments where we RDP into a secured secondary environment and had to edit code there. I see a browser-based IDE the next phase of something like that. Of course, you'd have to be able to set up this web-ide in a private corp environment.
But this is a good start for the indy web-developer working on certain types of projects.
Codio has keyboard shortcuts and they can all be customized. We are also adding a sublime like command bar and many other productivity focused features. We are adding a load of stuff for back-end development, too.
Codio is a complete, fully functional IDE, not a Codepen clone. We also have a lot of server side stuff coming out next week and server side support is an ongoing thing, as is offline editing, which will be coming out Q1 next year. We're still in Beta so we're listening hard!
(Freddy May from Codio)